The transportation industry plays an important role in the world economy. Diesel engines are still widely used as the main power generator for trucks, heavy machinery and ships. Removal technology for nitrogen oxides in diesel exhaust are of great concern. In this paper, a gas supply system for simulating the marine diesel engine exhaust is set up. An experimental study on exhaust denitration is carried out by using a dielectric barrier discharge (DBD) reactor to generate non-thermal plasma (NTP). The power efficiency and the denitration efficiency of different gas components by NTP are discussed. The exhaust gas reaction mechanism is analyzed. The application prospects of NTP are explored in the field of diesel exhaust treatment. The experimental results show that the power efficiency and energy density (ED) increase with the input voltage for this system, and the power efficiency is above 80% when the input voltage is higher than 60 V. The removal efficiency of NO is close to 100% by NTP in the NO/N₂ system. For the NO/O₂/N₂ system, the critical oxygen concentration (COC) increases with NO concentration. The O₂ concentration plays a decisive role in the denitration performance of the NTP. H₂O contributes to the oxidative removal of NO, and NH₃ improves the removal efficiency at low ED while slightly reducing the denitration performance at high ED. CO₂ has little effect on NTP denitration performance, but as the ED increases, the generated CO gradually increases. When simulating typical diesel engine exhaust conditions, the removal efficiency increases first and then decreases with the increase of ED in the NO/O₂/CO₂/H₂O/N₂ system. After adding NH₃, the removal efficiency of NO_x reaches up to 40.6%. It is necessary to add reducing gas, or to combine the NTP technology with other post treatment technologies such as SCR catalysts or wet scrubbing, to further increase the NTP denitration efficiency.

Life Cycle Assessment (LCA) methodology can be used to quantitatively assess the greenhouse gas emissions of low- or zero-carbon marine alternative fuels throughout their life cycle (from well to wake) and is an important basis for ensuring a green energy transition in the shipping industry. This paper first clarifies the trends and requirements of low-carbon development in shipping and introduces the major ship emission reduction technologies and evaluation methods. Next, the characteristics of various alternative marine fuels (i.e., LNG, hydrogen, methanol, ammonia, and biofuels) are comprehensively discussed and analyzed in terms of production, storage, transportation, and ship applications. In addition, this work provides a comprehensive overview of LCA methodology, including its relevant standards and assessment tools, and establishes a framework for LCA of marine alternative fuels. On this basis, a literature review of the current research on LCA of marine alternative fuels from the perspectives of carbon emissions, pollution emissions, and economics is presented. The case review covers 64 alternative-fueled ships and 12 groups of fleets operating in different countries and waters. Finally, this paper discusses the main shortcomings that exist in the current research and provides an outlook on the future development of LCA research of marine alternative fuels.

Hydrogen is considered to the ultimate solution to achieve carbon emission reduction due to its wide sources and high calorific value, as well as non-polluting, renewable, and storable advantages. This paper starts from the coastal areas, uses offshore wind power hydrogen production as the hydrogen source, and focuses on the combination of hydrogen supply chain network design and hydrogen expressway hydrogen refueling station layout optimization. It proposes a comprehensive mathematical model of hydrogen supply chain network based on cost analysis, which determined the optimal size and location of hydrogen refueling stations on hydrogen expressways in coastal areas. Under the multi-scenario and multi-case optimization results, the location of the hydrogen refueling station can effectively cover the road sections of each case, and the unit hydrogen cost of the hydrogen supply chain network is between 11.8 and 15.0 USD/kgH₂. Meanwhile, it was found that the transportation distance and the number of hydrogen sources play a decisive role on the cost of hydrogen in the supply chain network, and the location of hydrogen sources have a decisive influence on the location of hydrogen refueling stations. In addition, carbon emission reduction results of hydrogen supply chain network show that the carbon emission reduction per unit hydrogen production is 15.51 kgCO₂/kgH₂ at the production side. The CO₂ emission can be reduced by 68.3 kgCO₂/km and 6.35 kgCO₂/kgH₂ per unit mileage and per unit hydrogen demand at the application side, respectively. The layout planning utilization of hydrogen energy expressway has a positive impact on energy saving and emission reduction.

Solar energy as an abundant renewable resource has been investigated for many years. Solar thermoelectric conversion technology, which converts solar energy into thermal energy and then into electricity, has been developed and implemented in many important fields. The operation of solar–thermal–electric conversion systems, however, is strongly affected by the intermittency of solar radiation, which requires installation of thermal storage subsystems. In this work, we demonstrated a new solar–thermal–electric conversion system that consists of a thermoelectric converter and a rapidly charging thermal storage subsystem. A magnetic-responsive solar–thermal mesh was used as the movable charging source to convert incident concentrated sunlight into high-temperature heat, which can induce solid-to-liquid phase transition of molten salts. Driven by the external magnetic field, the solar–thermal mesh can move together with the receding solid–liquid interface thus rapidly storing the harvested solar–thermal energy within the molten salts. By connecting with a thermoelectric generator, the harvested solar–thermal energy can be further converted into electricity with a solar–thermal–electric energy conversion efficiency up to 2.56%, and the converted electrical energy can simultaneously light up more than 40 orange-colored LEDs. In addition to stable operation under sunlight, the charged thermal storage subsystem can release the stored heat and thus enables the solar–thermal–electric system to continuously generate electricity after removal of solar illumination.

Inspired by the “Lotus Leaf Effect” in nature, the phenomenon of superhydrophobia has attracted tremendous attention from researchers. Due to their special surface wettability, the superhydrophobic surfaces have been found to have broad potential applications in the fields of marine engineering, medical equipment, and aerospace. Based on the introduction of the principles of wettability, the advantages and disadvantages of various preparation methods for superhydrophobic surfaces were studied and summarized in this paper. The research progress on superhydrophobic surfaces in marine engineering applications was analyzed according to their self-cleaning, anti-corrosion, heat transfer, drag reduction, anti-fouling, ant-icing, and oil/water separation properties. Finally, to advance practical applications, the current challenges associated with superhydrophobic surfaces are highlighted, and potential future development directions are proposed.

With the rapid development of electronic technologies towards high integration, high power and miniaturization, thermal management has become an increasingly important issue to guarantee the reliability and service life of electronic devices. The oscillating heat pipe (OHP), which was governed by thermally excited oscillating motion, was considered as a promising technology to dissipate high-density heat and had excellent application prospects in many important industrial processes. A flat-plate OHP, however, was fabricated by traditional welding methods, which were difficult and inefficient, resulting in increasing the cost and wasting the production time. In this work, we adopted a new metal 3D printing technology to develop an aluminum flat-plate OHP, which made it facile to build complex inner channels with high-precision molding at one time. AlSi₁₀Mg powders, as raw materials, were selectively melted and solidified to form the container of the flat-plate OHP. The sintered inner surface presented excellent wettability to the working fluid, which facilitated the evaporation of the working fluid. Acetone was chosen as the working fluid, and the filling ratios with a range of 40–70% were loaded into the flat-plate oscillating heat pipe to analyze its effect on heat transfer performance. It was found that the 3D-printed flat-plate OHP with a 60% filling ratio had a better heat transfer performance and a lower thermal resistance, and it was able to work properly in both vertical and horizontal operation modes. The 3D-printed flat-plate OHP had been successfully applied for the thermal management of high-power LEDs, and the results showed that the temperature of LEDs was maintained within 60 °C, and its service life was prolonged.