In the face of increasingly severe energy shortage and environmental pollution, the use of new forms of energy will become an important direction for the future development of ships. A hybrid power ...system comprised of various types of energy, such as conventional fossil fuels, renewables, hydrogens, fuel cells and batteries, can ensure a continuous and reliable power source for ships by using different types of energy for various operating conditions. This has become an emerging solution for greener ships and attracted attention from both industry and academia. A state-of-the-art multi-energy hybrid power system for ships is introduced in this paper. The configuration and characteristics of series, parallel and series-parallel hybrid power systems are analyzed and compared. Challenges of multi-energy power system for large-scale ships such as reliability, control and efficiency are discussed, and possible solutions are proposed.
•Development of multi-energy hybrid power system, consisting of solar energy, energy storage, and diesel engines.•Key technologies to develop the multi-energy hybrid power system for ships.•Issues in the large-scale multi-energy ships, and suggestions to resolve these issues.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
► A practical laser device for pavement macrotexture measurement. ► Obtain three groups of macrotexture parameters. ► Seven types of pavement surface employed in system verification. ► The device can ...provide efficient, reliable, accurate and consistent measurements.
Pavement surface macrotexture greatly contributes to tire-pavement skid resistance which has a direct effect on traffic operation and safety particularly at high speeds. Therefore, efforts are needed to develop effective and practical devices to measure macrotexture profile. In this study, a practical laser device was developed, which is lightweight and portable with low cost. Following a critical review on existing devices, this paper outlines the hardware and software configurations of the proposed system. A comprehensive illustration on how the system works is presented to show a number of merits associated with the proposed device and accompanying analysis programs. Results from pilot testing experiments confirm that the proposed system provides efficient, reliable, accurate and consistent measurements for pavement surface profiles.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Wind energy plays a significant role in the energy consumption reduction of the sail-assisted vessels. During the navigation process, how to select the ideal airfoil sails is crucial for the vessel ...safety and wind energy conversion efficiency. We resolve the airfoil sails selection problem by utilizing computational fluid dynamics simulation. Within the computational fluid dynamics simulation approach, with shear-stress transport k–ω turbulence model, we analyze the performance of the three typical airfoil sails including NACA23012, NACA0012, and NACA0018 in the wind field from the perspective of force condition, lift and drag coefficients, and lift–drag ratio under generous wind speeds and angles of attack. And we investigate the pressure contours of the airfoil sails. Then, we can determine the aerodynamic performance of the airfoil sails promptly and identify suitable sails for the sail-assisted vessels under the given wind field.
•Analyse the primary data to estimate the appearance frequencies of risk factors resulting in maritime accidents.•Evaluate the joint impact of human factors and other risk factors on different types ...of maritime accidents.•Develop an accident data-driven Bayesian network to realise human factor oriented maritime accident analysis.•Conduct an empirical study to provide insights for the prevention of a particular type of accidents involving human errors.
A data-driven Bayesian network (BN) is used to investigate the effect of human factors on maritime safety through maritime accident analysis. Its novelties consist of (1) manual collection and analysis of the primary data representing frequencies of risk factors directly derived from maritime accident reports, (2) incorporation of human factors into causational analysis with respect to different maritime accident types, and (3) modelling by a historical accident data-driven approach, to generate new insights on critical human factors contributing to different types of accidents. The modelling of the interdependency among the risk influencing factors is structured by Tree Augmented Network (TAN), and validated by both sensitivity analysis and past accident records. Our findings reveal that the critical risk factors for all accident types are ship age, ship operation, voyage segment, information, and vessel condition. More importantly, the findings also present the differentiation among the vital human factors against different types of accidents. Most probable explanation (MPE) is used to provide a specific scenario in which the beliefs are upheld, observing the most probable configuration. The work pioneers the analysis of various impacts of human factors on different maritime accident types. It helps provide specific recommendations for the prevention of a particular type of accidents involving human errors.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In this study, stainless steel test plates with different surface roughness and textures, which are used as the heat transfer surface of a plate heat exchanger, are tested individually in calcium ...carbonate fouling experiments. The present experimental results clearly indicate a strong correlation between the surface roughness and the amount of crystallization fouling deposit. Through detailed image analysis, four stages of the formation of crystallization fouling are identified, and the impact of the surface morphology on the extent of crystallization fouling is described qualitatively.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A hydrogen fuel cell has many advantages, such as no pollution, high efficiency, low noise and continuous operation. Therefore, it has the potential to be widely applied in both the power propulsion ...and power supply of a ship. However, the consequent hydrogen safety and leakage issues have attracted much attention and become key issues that need to be resolved urgently. In this paper, based on the component transportation and chemical reaction modules in Fluent software, a ferry is selected as the research object, and a diffusion model of the high pressure hydrogen leakage in a cabin is established. The hydrogen concentration distributions at different leakage positions after the leakage occurs are obtained by making transient numerical calculations of the hydrogen leakage diffusion at the corresponding leakage positions in the cabin. At the same time, the effects of different ventilation conditions on the diffusion trend of hydrogen are analyzed. The simulation results have ascertained the optimal positions for hydrogen sensors and ventilations and it is hoped that these results can provide guidance for the design of a fuel cell ship that uses high pressure gaseous hydrogen.
•The safety of hydrogen fuel cell ship is researched by a CFD simulation.•The corners of fuel cell cabins are the areas with a higher concentration of hydrogen.•Reasonable ventilation is the most effective solution to hydrogen safety in cabin.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Recently, the melting of sea ice due to global warming has made it possible for merchant ships to navigate through Arctic Waters. However, Arctic Marine Transportation System remains a very ...demanding, dynamic and complex system due to challenging hydro-meteorological conditions, poorly charted waters and remoteness of the area resulting in lack of appropriate response capacity in case of emergency. In order to ensure a proper safety level for operations such as ship transit within the area, a risk analysis should be carried out, where the relevant factors pertaining to a given operation are defined and organized in a model. Such a model can assist onshore managers or ships’ crews in planning and conducting an actual sea passage through Arctic waters. However, research in this domain is scarce, mainly due to lack of data. In this paper, we demonstrate the use of a dataset and expert judgment to determine the risk influencing factors and develop a probabilistic model for a ship besetting in ice along the Northeast Passage. For that purpose, we adopt Bayesian belief Networks (BBNs), due to their predominant feature of reasoning under uncertainty and their ability to accommodate data from various sources. The obtained BBN model has been validated showing good agreement with available state-of-the-art models, and providing good understanding of the analyzed phenomena.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Gaskets are applied in PEMFCs (proton exchange membrane fuel cells) to keep reactant gases and liquid within their respective regions, which are of great significance for the both sealing and ...electrochemical performance of fuel cells during the long-term operation. In this study, the degradation of silicone rubbers, often selected as seals in PEMFCs, in Fenton’s reagents with different H
2
O
2
concentrations was investigated. The changes in chemical properties, mechanical behavior and surface morphology of the samples were studied before and after exposure to the test environment over time. It is found that increasing H
2
O
2
concentration will degrade the rubbers more severely. The experimental results elucidate the degradation mechanism of silicone rubbers in Fenton’s reagents and the influence of H
2
O
2
in the degradation process.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Due to the increasing demand for energy conservation and the reduction of emissions, renewable energy applications for ships have attracted a great deal of attention. In this paper, a 5000-vehicle ...space pure car and truck carrier (PCTC) is selected as the research object. Then, on the basis of the existing power system, a unified grid-tied/stand-alone solar system is designed with a built-in battery energy storage system. The system includes a solar energy generation unit, a battery storage system, a diesel generating set, grid-tied/stand-alone controlled inverters, a battery management system (BMS) and an energy management system. According to an analysis of the experimental data, it can be concluded that the use of solar energy hybrid power, in theory, can reduce fuel consumption by 4.02% and carbon dioxide (CO2) emissions by 8.55% a year.
•A large-scale hybrid PV/diesel ship power system is designed.•The energy saving and emission reduction effects are analyzed through an experimental test.•Ships using this PV hybrid power system can effectively reduce fuel consumption.•The PV hybrid power system design scheme can provide significant guidance for the same type of ships.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The tribological properties of ZrO
2
ceramic and 1Cr18Ni9Ti stainless steel rubbing pairs were investigated using a special tribotester under different concentrations of hydrogen peroxide (H
2
O
2
) ...solution. The comparison analyses of the friction coefficients, worn volume rates, worn particles and surface roughness were conducted under the tested conditions. There were significant differences of the tribological properties of the rubbing pairs in the different concentrations H
2
O
2
solution because of oxidation and corrosion. This research has revealed that the main wear mechanisms between the rubbing pairs are severe adhesive wear, abrasive wear and corrosive wear in the H
2
O
2
solution with different concentrations. A model has been established to assess the most suitable concentration of the H
2
O
2
solution for the tribological properties of the rubbing pairs. The result shows that 50% concentration of the H
2
O
2
solution is the most suitable. The assessment result is consistent with the experimental result. It is believed that the knowledge gained in this study is useful for the optimization of the friction pairs in the extreme condition.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
