In this paper, a new integrated system of solid oxide fuel cell (SOFC)–gas turbine (GT)–steam Rankine cycle (SRC)–exhaust gas boiler (EGB) is presented, in which ammonia is introduced as a promising fuel source to meet shipping decarbonization targets. For this purpose, an SOFC is presented as the main power-generation source for a specific marine propulsion plant; the GT and SRC provide auxiliary power for machinery and accommodation lighting, and steam from the waste heat boiler is used for heating seafarer accommodation. The combined system minimizes waste heat and converts it into useful work and power. Energy and exergy analyses are performed based on the first and second laws of thermodynamics. A parametric study of the effects of the variation in the SOFC current density, fuel utilization factor, superheat temperature, and SRC evaporation pressure is conducted to define the optimal operating parameters for the proposed system. In the present study, the energy and exergy efficiencies of the integrated system are 64.49% and 61.10%, respectively. These results serve as strong motivation for employing an EGB and SRC for waste heat recovery and increasing the overall energy-conversion efficiency of the system. The SRC energy and exergy efficiencies are 25.58% and 41.21%, respectively.

In order to cope with strengthened marine environmental regulations and to reduce fuel consumption, recently constructed vessels are equipped with an ultra-long stroke engine and apply engine de-rating technology. This was intended to improve propulsion efficiency by adopting a larger diameter propeller turning at a lower speed but also results in a significant increase in the torsional exciting force. Therefore, it is very difficult to control the torsional vibration of its shaft system by adopting a damper, for ships equipped with fuel-efficient ultra-long-stroke engines, even though previously, torsional vibration could be controlled adequately by applying tuning and turning wheels on the engine. In this paper, the vibration characteristics of an ultra-long-stroke engine using the de-rating technology are reviewed and dynamic characteristics of a viscous-spring damper used to control the torsional vibration of its shaft system are also examined. In case of ships have recently experienced an engine acceleration problem in the critical zone, it is proposed that the proper measures for controlling torsional vibration in the propulsion shafting system should include adjusting the design parameters of its damper instead of using the optimum damper designed from theory in order to prevent fatigue fracture of shafts.

The Chemical Substances Control Act emphasizes the importance of proactive planning for chemical accident prevention and response, requiring facilities handling hazardous chemicals to develop and submit comprehensive plans in compliance with regulatory standards. Among these measures, the designation of chemical accident evacuation sites is considered a critical step to protect local residents and mitigate the impact of accidents. Despite the significance of evacuation site planning, existing research has primarily focused on the general conditions and locations of evacuation sites, with limited attention to their selection process and safety evaluation. This study aims to bridge this gap by evaluating the suitability of evacuation site locations through detailed risk assessments. Using tools such as KORA and ALOHA, the study analyzes the impact range under seasonal meteorological conditions. The limitations of current evacuation sites were assessed, and additional sites were proposed, considering the number of evacuees able to travel on foot during emergencies. The study highlights the importance of selecting evacuation sites based on seasonal weather conditions and provides actionable recommendations to improve public safety and minimize risks during chemical accidents. The findings of this study are expected to contribute to the advancement of emergency response systems, promoting a safer and more resilient environment for both local communities and industrial facilities.