Journal of Marine Technology and Environment 2023 Vol. 1

Refrigeration is an industry of high importance in our modern times. It plays also a key role in maritime transport of perishables, where vapour compression refrigeration systems are dominant. These energy systems are indispensable, but they should be wise exploited because their high energy necessity. One of the frequent refrigerant chemical adopted in this system is the hydrofluorocarbon R134a. This refrigerant came to substitute traditional refrigerants, such as chlorofluorocarbons or hydro chlorofluorocarbons – substances being under environmental regulations. In this study, it is approached a single stage vapour compression refrigeration system working with R134a. The aim is to find the conditions in which this system is more energy efficient. In this respect, based on the laws of thermodynamics, are obtained information on Coefficient of Performance and energy destruction trends – when the evaporator temperature increases. Our results indicate that, although the analysis based on the first law of thermodynamics reveals that the performance of the system is higher for high evaporator temperatures, the energy destructions in this system increase together with the evaporator temperature increase.

Through the 1978 SOLAS Protocol and then through the introduction of amendments from 1981 and 1983, new specifications are brought regarding the design, operation, maintenance, verification of inert gas systems intended for both oil tanks and bulk chemical tanks, and, in general, the systems of safety on board ships carrying dangerous goods. The inerting method using a gas system with generator and scrubber involves a continuous and very efficient process, with a low level of supervision and maintenance, that is why this type of installation was chosen in this study. Installations with a scrubber type unit require the installation of an inert gas generator that operates at a pressure of 8-10 bar and releases nitrogen at 7-9 bar. The quality of the air will depend on the type of generator used, scrubber type unit, but air without impurities with the best possible quality is recommended. Nitrogen quality for a given unit varies with production rate and is generally 95-97% pure. By connecting high-quality scrubbers, nitrogen can be brought to 99% purity, but at lower production rates and much higher energy consumption rates of any system on board ship is specifically identified with its reliability. So as to get the best out of marine motors, it is critical to screen their performances and take measures to accomplish productive combustion. As a result of heat gains on board ships from engine rooms and crew, the increase in humidity as well as due to the various releases of gases from on board systems, room air deteriorates, requiring replacement and its processing through the HVAC (heat, ventilation and air conditioning) system. The combustion process in diese.

Centrifugal pumps are most commonly used pumping devices in industry their being fit for pumping water. There are several types of centrifugal pumps, their differences in construction is due to their size and how cloggy the pumped water is. In the paper it was simulated a 2D centrifugal pump of small size used in daily activities. The simulation, performed with CFD (ANSYS-Fluent), was made for different inlet velocities of water. Different parameters, such as inlet pressure, outlet pressure, maximum velocity and flow rate, were calculated and graphically represented against inlet velocity. Also, graphical representation of pressure distribution .

One of the main causes of accidents on board ships is fire. This is because of the presence of high temperature, the excess quantity of flammable oil and other combustible materials. A ship is fitted with various types of fire retardant and firefighting equipment so as to fight any kind of fire and extinguish it as soon as possible before it turns into a major catastrophic situation. Purpose: This paper presents the crisis management on ship’s firefighting plant, Technical data for firefighting plant with foam, Fault Tree Analysis data, Fault tree block diagram, Failure probability and basic events of fault tree, The equations of fire analysis, The method of simulation, The simulation of a fire incident in the firefighting plant, for a ship named "Mamola Defender" which is a vessel that provides the supply of marine drilling platforms. The results are: Foam firefighting plant diagram, Locations for firefighting systems, Fire Control and Safety Plans, Fault tree block diagram, The values of probabilities, The relationship between input and output events. The results of simulation for a scenario are: radiant heat distribution of a jet fire, the heat flux, the temperature distribution on different stage of fire, the flame propagations. Conclusions: The methods which used for simulation present a possible fire incident in a plant with many hazardous materials. This method of simulation is useful to assistance plant owners and operators in different events of emergency situations. This methodology is useful to prevent human casualties and important structures.

This paper presents the main complicate science issues man has to solve, but it also presents reasons to explain his present incapacity to solve them. It also shows ways to address more successfully those complicate issues, in order to find their solutions.

This paper is concerned with the logic of happiness, whereas happiness is most commonly seen by man as a function of fulfilled wishes. It also shows the disastrous consequences for man and his home planet when engaging in this damaging way to search for happiness. This paper also shows that the main reason for consume and overuse of planet’s resources is that man has been trained to consumerism by various tactics and strategies which were applied to him in the recent past, with the purpose of making him “successful” and a “good” citizen. This paper also provides some more conventional and some more nonconventional solutions to undone this evil of the “induced” necessity to consume in order to be happy.

Showing complicate issues in science, like the strange facts and realities pertaining to the quantum world, this paper explains why it is so difficult to understand and to solve those complicate issues. This paper also stresses the important fact, that in order to understand these strange realities pertaining to the quantum phenomena but also in order to solve other complicate problems of science such as the climate change issues, one should give up the traditional way of thinking of the science and should also renounce the false idea of the rationalism, stating that the entire reality can be known and understood by using scientific reasoning.

Adding of nanoparticles in a base working agent leads to Nano fluids representing of a new type of working fluid. Due to an increase surface area, there is a gain in the surface area needed for heat transfer between nanoparticles and base fluid. Sein the poor heat transfer properties of water, water base Nano fluids present improved heat transfer performance and require smaller heat exchangers. This paper deals with the estimation of specific heat transfer capacity of water-Al2O3 Nano fluid. The decrease of volume concentration, from 13% to 3%, will reveal a gain in SHC of 27% - for nanoparticles diameter of 60 nm and a gain of 40% - for 30 nm diameter. At high temperature, SHC shows better values, also when the volume concentration is lower.

This paper aims to highlight the devastating impact of the imposed restrictions during the COVID-19 Pandemic towards the mental health of the sailing crew. It is well known that the employees in the navy domain were already accustomed to distinct working conditions, depriving themselves of factors that are vital for a balanced, functional state of mental health. The seamen are subjected to solitude, uncertain and unpredictable weather, a constant fear of danger and the anxiety of being prepared to ensure their own safety at any time needed. This paper aims to highlight the devastating impact of the imposed restrictions during the COVID-19 Pandemic towards the mental health of the sailing crew. Isolation, research shows, has an impact on both mental and physical health, from reducing the ability to manage stressful situations, to difficulties in making decisions, memorizing and processing information to the onset of depression, anxiety, attacks of panic and increasing the risk of illness, because the immune system of a person responds differently in the fight against viruses. In this paper were presented the procedures that the crew members of the ships that made voyages in the areas where the imposed restrictions were among the toughest to follow. Also, the mental state of the crew during the voyage and after arrival were analyzed, from in terms of the staff's statements but also individually.

Passing from school to the labour market requires support, advice, and guidance. The rapid advancement of technology in the maritime industry, the wide range of duties, and ever-changing job placement from ashore to remote sites or on board vessels, put many treats on the future employees. This article describes how career counselling is integrated into the process of supporting VET learners in making decisions about future careers in three European countries and how this process is perceived by learners. The research comprised a literature review to reveal the approach with regard to career counselling and analysis of data collected with a survey questionnaire. The 88 responses emphasized learners' views regarding the career counsellor’s actual role and provided an understanding of their expectations for making the transition toward the labour market. The questions addressed groups of people that decided to continue their studies and get a job and those undecided. Participants explained the motivator factors for making the career choice, the main sources of career information, and their expectations from the future job. This article explores the extent to which the professionals and counsellors would contribute to making the decisions and the types of interaction that are expected to produce positive results and engagement. The results indicate that teachers and parents are currently contributing to making the final career decision. Even though, the input of professionals is highly expected by all groups of participants. Respondents emphasized that challenges, dynamism in the workplace as well as the variety of tasks are those factors that would make them stay in a job. The authors concluded that to be effective, the career counselling of young learners needs to be enriched with jobspecific insights provided by professionals. The research conclusions draw up the VET learners' main expectations that can be used to guide further career counselling activities.