Journal of Marine Technology and Environment 2026 Vol. 1

This study investigates the thermal balance of a MAN B&W 6S50ME-C two-stroke marine engine operating as the main propulsion system of a 40,000 DWT Oil/Chemical Tanker. Within the current maritime context, where fuel efficiency and emission reduction have become major priorities, a clear understanding of how thermal energy is distributed inside large marine engines is essential for performance optimization and energy recovery solutions. The objective of the paper is to determine how the energy released during fuel combustion is converted into useful mechanical work and how it is dissipated through various loss mechanisms. The analysis is based on a detailed thermal balance calculation using real operational data, such as effective engine power, specific fuel consumption, cooling fluid flow rates, lubrication oil parameters, and exhaust gas temperatures. The applied methodology consists of thermal balance calculations based on established thermodynamic relations, expressed in absolute, relative and percentage terms. The results indicate that approximately 40.98% of total thermal energy supplied by the fuel is transformed into effective mechanical output. A significant part of the remaining energy is lost through exhaust gases, accounting for about 29.37%, while cooling systems represent approximately 22.32% of total losses. Additional minor losses, including radiation and mechanical friction represent around 7.04%.The analysis confirms that exhaust gas losses constitute the dominant source of recoverable thermal energy. Consequently, the study highlights the importance of exhaust heat recovery systems as an effective means to improve overall engine efficiency, reduce fuel consumption, and support more sustainable marine propulsion operations.

A method for determining the optimal operating modes of marine diesel exhaust gas bypass systems is considered. The aim of this research was to determine the optimal volume of exhaust gas bypass for a marine medium-speed diesel engine, specifically the 6L20 Wartsila. Electronic engine control allows flexible adjustment of exhaust gas bypass process within a range of 0 to 10 % of the total volume of gases exiting the diesel cylinder. The use of exhaust gas bypass contributes to improving the environmental performance of marine medium-speed diesel engines, particularly in the operational load range of 55–85 %, where NOx emissions in exhaust gases decrease by 3.5–15.4 %. The greatest reduction in NOx emissions occurs at loads of 75–85 %. The use of the exhaust gas bypass system is deemed effective for loads exceeding 75 %, with potential reductions in nitrogen oxide emissions ranging from 9.2 % to 15.4 %. For loads of 55–65 %, a reduction in nitrogen oxide emissions (3.3–5.6 %) is also observed, but with a simultaneous increase in specific fuel oil consumption (4.2–4.4 %). However, for certain bypass values, the diesel engine's thermal stress exceeds acceptable limits.

The paper compares two methods of generating inert gas on ships. The advantages and disadvantages of two inert gas generators are considered: membrane nitrogen generator and combustion-type generator. Based on the analysis of electricity and fuel consumption of both systems, it was shown that the membrane nitrogen generator outperforms the combustion-type inert gas generator. Specific fuel consumption for a nitrogen generator (at 5 % of oxygen on inert gas) is more than two times less compared with a combustion-type one: 34.8 kg/nm3 vs 78.5 kg/nm3. However, when the required oxygen content in the inert gas decreases, the membrane nitrogen generator will be inherent in higher electricity consumption, requiring further analysis of its feasibility compared to the combustiontype one.

This study is framed by the accelerating displacement of fossil energy carriers, driven by depletion and externalities (GHG emissions and ecosystem impacts), and by the global shift toward converter-interfaced variable renewable energy (VRE). The objective is to justify, using recent deployment evidence, why next-generation photovoltaic (PV) and wind energy conversion system (WECS) technologies constitute the highest-leverage innovation targets for near-term capacity scale-up and grid-compatible decarbonization. Methodologically, the work combines (i) macro-trend interrogation of IRENA renewable capacity statistics (2015–2024) with (ii) a structured technology review of emerging wind concepts (vortex-induced vibration bladeless harvesters, passive/ducted building-integrated turbines, and modular multi-rotor architectures) and advanced PV architectures (bifacial modules and transparent PV/TLSC devices), focusing on dominant physical mechanisms, conversion chains, and deployment constraints. Results show that 2024 delivered a record +585 GW (+15.1%) renewable capacity expansion, with PV (+452 GW; +32.2%) and wind (+113 GW; +11.1%) contributing 96.6% of net additions, whereas hydro, bioenergy, and geothermal exhibited marginal growth. Key technology bottlenecks are identified: resonance-bandwidth limits in VIV harvesters (addressable via adaptive stiffness tuning), aerodynamic losses and siting dependence in passive systems, and load/wake management in multi-rotor arrays; bifacial PV bankability remains coupled to rear-irradiance modelling and mismatch control, while TPV is constrained by the transparency-efficiency trade-off. The findings indicate that accelerating PV/WECS innovation is pivotal for sustained renewable expansion under realistic environmental variability.

Neuromarketing is an emerging interdisciplinary field that combines neuroscience with marketing research to uncover insights into consumer behavior at the neural level. This article offers an academic examination of how neuromarketing techniques are applied in modern marketing practices and analyzes their implications for consumer decision-making. The study outlines the theoretical foundations of neuromarketing, including its methods for investigating consumers’ subconscious responses. Key findings indicate that neuromarketing has significantly influenced areas such as advertising design, branding strategies, pricing tactics, and product development by revealing unspoken preferences and emotional reactions from consumers.

On board of ships, cascade refrigeration systems are used when both frozen and refrigerated products are transported. In such a situation, two different levels of temperature are ensured in the same time. There are needed two conventional refrigeration systems which are coupled by a cascade heat exchanger. Thermodynamic analysis of these systems are important when aiming efficient design and performance optimization. The main objective of this paper is to present different analysis means such as energy, exergy or thermoeconomic (exergoeconomic). Also, there are analysed the challenges to be faced by engineers when developing a thermoeconomic analysis of cascade vapour compression refrigeration systems. Thermoeconomics analysis is a “sensitive issue” due to the interdisciplinary approach, being combined concepts of economics and thermodynamics to evaluate cost formation process of these thermal systems.

Commercial vessels with large deadweight capacity engaged in international voyages are generally powered by a single propeller. Hence, because the responsibility for developing the thrust force lays upon a single thrust component and redundancy cannot be ensured, a comprehensive evaluation for the operational conditions is to be carried out, as the propeller is closely related with the hydrodynamic seaworthiness of the vessel, which should precede any propulsion analysis, [1-2]. Despite the proven reliability of the nickel–aluminium-bronze alloy (NAB hereafter) used in its manufacturing, a marine propellers exposed to the risk of extended cavitation, the propeller is prone to localised wear and surface degradation. This is the reason of the present research aimed at is addressing the problematics of cavitation erosion of NAB propellers by employment of CFD investigation instruments. Cavitation occurrence is emphasised on a simplified three blades propeller together with hydrodynamic characteristics evaluation. Hence, the initiation of the cavitation on the blades surfaces is described together with a brief introduction of the most commonly used mitigation and recondition techniques of cavitation affected areas of propeller blades through modern methodologies.

Since its inception in 1991, the DDG-51 naval class vessel continues to be a workhorse for the US Navy. In the coming three decades, naval performance is expected to be influenced by climate change. We would like to investigate whether the current marine diesel run vessel will benefit from retrofitting any other technology to tackle climate change impact and contribute to a greener operation. We argue that substituting diesel with methane gas while retrofitting with air lubrication can indeed lend help to this effort. More technically, drawing inspiration from maritime logistics, we arrive at our conclusion that the conventional diesel run DDG-51 naval vessel with air lubrication will offer similar CO2 per ton nautical mile emissions and related costs per ton nautical mile like the environmentally better methane gas fuel run without air lubrication. We thus conclude that the methane gas run vessel with air lubrication is better than diesel run vessel with air lubrication. This conclusion is shown to be valid via a climate scenario projection for three decades into the future.

Parametric rolling is a resonance phenomenon affecting the safety and operational performance of ships, especially in head or following seas. This paper investigates the possibility of attenuation of parametric roll oscillations by using rudder-based stabilization. To this goal, the ship is represented as a single-degree of freedom oscillator with nonlinear damping and time-varying nonlinear stiffness, subjected to a proportional-derivative (PD) control applied via the rudder. Numerical simulations are performed to measure the influence of the main model parameters, including control gains, initial conditions, encounter wave frequency, on the ship response in roll. Results demonstrate that PD rudder control are able to reduce substantially roll amplitudes for an extensive range of operating conditions. The findings provide insight into the effectiveness of rudder-based control of ship rolling and can be used as a foundation for future research using more complex ship models. Key words: parametric roll, rudder-based control.

Journal of Marine Technology JMTE has come of age. This year, it’s celebrating its 18th birthday! His journal has ISSN (Print): 1844-6116 ISSN (Online): 2501-8795 (from Volume 2/2016 to present). Number of articles published over the years: 2008, issue 1-14 articles; 2009-issue 1,15 articles; issue 2, 19 articles; 2010-issue 1,33 articles; issue 2-23 articles; 2011-issue 1,issue 2,17; 2012-issue 1,20; issue 2,13; 2013-issue 1,20; issue 2,16; 2014-issue 1,11; issue 2,13; 2015-issue 1,13; issue 2,13;l 2016-issue 1,11; issue 2,12; 2017-issue 1,11; issue 2,17; 2018-issue1,9; issue 2,6; 2020-issue 1,6; issue 2,8; 2021-issue 1,7; issue 2-11; 2022-issue 1, 12; issue 2, 10; 2023-issue 1,10; issue 2,14; 2024-issue 1,11; issue 2,9; 2025-issue 1,11; issue 2,9; 2025-issue 1,12; issue 2,11. From 2008 to 2015, the editor-inchief was Associate Professor Feiza Memet, Ph.D., Eng., and from 2016 to the present, it has been Professor Mariana Panaitescu, Ph.D., Eng. Initially, the journal published a short abstract. Later, the full-length articles were published. Between 2013 and 2015, the journal was indexed in Copernicus (ICV 2013: 5.69; ICV 2015: 72.06). The Editorial team is currently working to index the journal in other internationally recognized databases. As of 2026, the journal is open access (Creative Commons Attribution 4.0 International License).