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The use of computational fluid dynamics (CFD) to predict internal and external flows has risen dramatically in the past decade. This research aims to use the commercial software, ANSYS Fluent V.14.5, to illustrate the effects of the rudder and blade pitch on the hydrodynamic performance of the marine propeller by experimenting with propellers and rudders of the M/V Tan Cang Foundation ship, which has designed conditions as follows: diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m; boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller and some important results showed that the maximum efficiency of the propeller is 0.66 with the open water propeller and 0.689 with the rudder‒propeller system at the advance ratio of 0.6. The obtained outcomes of this research are a significant foundation to calculate and design an innovative kind of propulsion for ships with high performance.

In this work, we proposed to synthesize CuFe2O4/Fe2O3 core-shell materials with different Fe2O3 contents in order to create new and efficient photo-Fenton-like catalysts for the degradation of methylene blue with oxalic acid as a radical-producing source. The catalysts were prepared through two stages: first, CuFe2O4 was prepared by a hydroxide coprecipitation – annealing method and then, Fe2O3 was immobilized on CuFe2O4 surface by a simple impregnation – annealing procedure. According to the experimental results, our CuFe2O4/Fe2O3 core-shell materials exhibit high photo-Fenton-like catalytic activity for the degradation of methylene blue under both UVA light and visible light, as well as good ferromagnetic properties, which allows them to be easily separated from the solution by a magnet. Among them, the catalyst prepared with the molar CuFe2O4/Fe2O3 ratio of 1:2 showed the best catalytic performance with the rate constant of 2.103 h–1 under UVA light and 0.542 h–1 under visible light, which were 2 times higher than CuFe2O4 sample. The enhanced catalytic activities of our core-shell materials can be attributed to the high content of surface Fe3+ species, high specific surface area and the presence of rod-like Fe2O3 particles on their surface.

Maritime shipping is one of the most important activities of the global economy, with outstanding advantages in terms of volume and distance. According to projections by the International Transport Forum, Global demand for marine transportation is expected to grow dramatically over the next three decades. Along with that, maritime activities emit large amounts of greenhouse gases and other harmful emissions, causing negative impacts on the environment. Energy consumption trends (ECT) are formed by the application of potential emission reduction solutions such as technical improvement, use of alternative fuels, efficient and economical use of fuel and optimal vessel operation. However, ECT is, an issue related to various criteria to be assessed. The goal of this study is to make science assessment of ECT which can be developed national ship emission reduction strategy. Availability of energy supply and use, emission reduction potential, economic efficiency were simultaneously considered to evaluating ECT to cut GHG emission from shipping by using Fuzzy Analytic Hierarchy Process combined with opinions of 46 experts. The results show that hydrogen fuel ranks highest in ECT as the future fuel of the maritime industry. The findings of this study are expected as an important platform to develop national ship emission reduction strategy planning. [ABSTRACT FROM AUTHOR]