Overview of Past, Present and Future Marine Power Plants

In efforts to overcome an foreseeable energy crisis predicated on limited oil and gas supplies, reserves; economic variations facing the world, and of course the environmental side effects of fossil fuels, an urgent need for energy sources that provide sustainable, safe and economic supplies for the world is imperative. The current fossil fuel energy system must be improved to ensure a better and cleaner transportation future for the world. Despite the fact that the marine transportation sector consumes only 5% of global petroleum production; it is responsible for 15% of the world NOx and SOx emissions. These figures must be the engine that powers the scientific research worldwide to develop new solutions for a very old energy problem. In this paper, the most effective types of marine power plants were discussed. The history of the development of each type was presented first and the technical aspects were discussed second. Also, the fuel ceils as a new type of power plants used in marine sector were briefed to give a complete overview of the past, present and future of the marine power plants development. Based on the increased worldwide concerns regarding harmful emissions, many researchers have introduced solutions to this problem, including the adoption of new cleaner fuels. This paper was guided using the same trend and by implementing the hydrogen as fuel for marine internal combustion engine, gas turbines, and fuel cells.

Thermodynamic Analysis of a Condensate Heating System from a Marine Steam Propulsion Plant with Steam Reheating

The thermodynamic(energy and exergy)analysis of a condensate heating system,its segments,and components from a marine steam propulsion plant with steam reheating is performed in this paper.It is found that energy analysis of any condensate heating system should be avoided because it is highly influenced by the measuring equipment accuracy and precision.All the components from the observed marine condensate heating system have energy destructions lower than 3 kW,while the energy efficiencies of this system are higher than 99%.The exergy efficiency of closed condensate heaters continuously increases from the lowest to the highest steam pressures(from 70.10%to 92.29%).The ambient temperature variation between 5℃and 45℃notably influences the exergy efficiency change of both low pressure heaters and the low pressure segment equal to 31.61%,12.37%,and 18.35%,respectively.

The coastal medicinal plant Vitex rotundifolia: a mini-review on its bioactive compounds and pharmacological activity

Humans have long used natural remedies like plants and herbs to treat disease.Furthermore,research has been ongoing to find alternative pharmaceutical drugs based on traditionally used plants,as natural products show fewer side effects compared to synthetic drugs.Medicinal plants have long been targeted in drug development due to their bioactive compounds like alkaloids,flavonoids,and terpenoids.This is not only the case for terrestrial plants,but marine environments also provide a larger diversity of flora and fauna with medicinal bioactive compounds.Vitex rotundifolia,also known as Beach Vitex,is a coastal plant that has been traditionally used to treat a variety of diseases including premenstrual syndrome,headaches,migraines,colds,and eye pain.There have been many review papers on V.rotundifolia,emphasizing its taxonomy,distribution,and biological activity.Our current mini-review not only summarizes the pharmacology and bioactivity of V.rotundifolia,but it also provides new information on the main bioactive compounds of V.rotundifolia such as flavonoids,phenolic acid,and terpenes and their current pharmacological activity in vitro and in vivo research.This information can be useful for developing new pharmaceutical and nutraceutical agents to treat and manage disease.

基于元启发式算法的船舶动力装置随机建模与性能优化

For the successful operation of any industry or plant continuous availability of power supply is essential.Many of the large-scale plants established their power generation units.Marine power plant having two generators is also fall in this category.In this study,an effort is made to derive and optimize the availability of a marine power plant having two generators,one switch board and distribution switchboards.For this purpose,a mathematical model is proposed using Markov birth death process by considering exponentially distributed failure and repair rates of all the subsystems.The availability expression of marine power plant is derived.Metaheuristic algorithms namely dragonfly algorithm(DA),bat algorithm(BA)and whale optimization(WOA)are employed to optimize the availability of marine power plant.It is revealed that whale optimization algorithm outperforms over dragonfly algorithm(DA),and bat algorithm(BA)in optimum availability prediction and parameter estimation.The numerical values of the availability and estimated parameters are appended as numerical results.The derived results can be utilized in development of maintenance strategies of marine power plants and to carry out design modifications.

Discussion on Foundation of Offshore Wind Turbine

This paper briefly describes the classification and composition of offshore wind turbine foundation structure,and focuses on different structural forms of offshore wind turbine foundation.The advantages,disadvantages and application fields of offshore wind turbine foundations with different structures are compared and analyzed.Finally,some suggestions on the construction of offshore wind power foundation are put forward.