No abstract

In this article, the operation of a large containership main engine was investigated with emphasis at slow steaming conditions. A cycle mean value approach implemented in the MATLAB/Simulink environment was adopted to simulate the two-stroke marine diesel engine due to the fact that it combines simplicity with adequate prediction accuracy. For accurately representing the compressor performance when the engine operates at low loads, the extension of the compressor map at the low rotational speed region was carried out based on a non-dimensional parameters method incorporating a novel way of calculating the compressor isentropic efficiency. The compressor map extension method results were validated using a corrected similarity laws approach. The engine steady state operation for various loads was simulated and the predicted engine performance parameters were validated using shop trial measurements. Furthermore, the engine transient operation in the load region below 50% was studied and the simulation results including the compressor operating points trajectory are presented and discussed. Based on the obtained results, the influence of the activation/deactivation of the installed electric driven blowers and the turbocharger cut-out on the engine operation was analysed

This paper presents a novel forward dynamic programming method for weather routing to minimise ship fuel consumption during a voyage. Compared with traditional weather routing methods which only optimise the ship's heading, while the engine power or propeller rotation speed is set as a constant throughout the voyage, this new method considers both the ship power settings and heading controls. A float state technique is used to reduce the iterations required during optimisation and thus save computation time. This new method could lead to quasiglobal optimal routing in comparison with the traditional weather routing methods

By adopting the concept of modularity, this paper introduced an optimal framework which facilitates life cycle assessment and life cycle cost assessment, thereby supporting rapid and reliable decision-making in the marine industry. The benefits of the proposed framework were discussed through two case studies where the optimal configurations of marine propulsion systems were determined from the economic and environmental perspectives. First, the performance of a short-route ferry using the hybrid system was compared with those of equivalent ships using diesel-electric and diesel-mechanical propulsion systems respectively. Research findings revealed the excellence of the hybrid system in both economic and environmental aspects. Second, the same method was applied to an offshore tug vessel to determine an optimal engine configuration. Results of analysis emphasised that the selection of multiple small-sized engines is more effective than two medium-sized engines. Both studies have proven that the proposed framework would be useful and practical for accelerating the life cycle analysis which allows ship designers and owners to obtain the long-term view of economic and environmental impacts for particular products or systems without demanding process. The paper also opened up the possibility of extending the application of the proposed framework to the areas where proper decision-making is essential but under-used.

The study performed a life cycle assessment (LCA) of a molten carbonate fuel cell (MCFC) plant for marine applications. The results are compared to a benchmark conventional diesel engine (DE) which operates as an auxiliary power generating unit. The LCA includes manufacturing of MCFC and DE, fuel supply, operation and decommissioning stages of the system's life cycle. As a new technology in its very early stages of commercialisation, some detailed data for the FC systems are not available. In order to overcome this problem, a series of scenario analysis has also been performed to evaluate the effect of various factors on the overall impact, such as change in power load factors and effect of recycling credit at the end of life cycle. Environmental benefits from fuel cell operation are maximised with the use of hydrogen as an input fuel. For the manufacturing stage of the life cycle, input material and process energy required for fuel cell stack assemblies and balance-of-plants (BOP) represent a bigger impact than that of conventional benchmark mainly due to special materials used in the stack and the weights of the BOP components. Additionally, recovering valuable materials through re-use or re-cycle will reduce the overall environmental burden of the system over its life cycle

No abstract

• Bioinspired by natural superhydrophobic surface with hierarchical micro-nanostructures, waterproof artificial compound eyes with variable field of view (FOV) were fabricated by a simple and effective manufacturing method. • The fabricated artificial compound eyes exhibited excellent waterproof property, tunability of the FOV and optical performance.

Two types of nylon-1010/MMT nanocomposites were successfully prepared by melt intercalation using a corotating twin-screw extruder. The nanocomposites were characterized with X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). It was found that the difference in the properties of the two types of the organo-MMTs directly influences the structure and the properties of the obtained nanocomposites. The results of XRD and TEM showed that the DK2-MMT nanocomposites possess an exfoliated structure and the nanocomposites containing 16C-MMT exist as intercalated structures. The mechanical properties of the nylon-1010/organoMMTs nanocomposites were better than those of the pure nynon-1010. In addition, the properties of the DK2-MMT nanocomposites were superior to those of the 16C-MMT nanocomposites because of the different dispersibility of the two organo-MMTs. The thermal stability of the nanocomposites was improved. The storage moduli of the nanocomposites increased and the glass-transition temperature shifted to a slightly higher temperature because of the introduction of the organo-MMTs. The addition of DK2-MMT into the nylon-1010 matrix accelerated the crystallization rate of the matrix.