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Owing to the vulnerability of Invar to moisture in the membranes of LNG tanker cargo tank construction platforms (CTCPs), an energy-efficient ventilation system is needed to maintain a suitable thermal-moisture environment and a healthy workplace. However, the optimal distribution of supply and return devices that would guarantee worker satisfaction, air quality, and energy efficiency is unclear. Therefore, we conducted numerical simulations to determine the worker satisfaction indices (temperature, relative humidity, and carbon monoxide concentration satisfactions), air quality index (contaminant-removal efficiency), and energy efficiency index (heat-removal efficiency) with supply vane angles ranging from -75° to 0° and two return vent positions (the bottom return vent and the top return vent). The analytic hierarchy process (AHP) entropy weight method was employed to determine the optimal supply vane angle and return vent position for three design targets by considering these indices simultaneously. The results indicated that, with a supply angle of -45° and a bottom return vent, worker satisfaction and air quality were prioritized. Furthermore, a high energy performance of the ventilation system was achieved with a -15° supply angle and a bottom return vent. Moreover, a comprehensive graph of supply vane angles at both return heights, which could provide a reference for optimizing the ventilation system in LNG-CTCPs, is described. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2), as an alternative electrocatalyst, has great potential to drive the hydrogen evolution reaction (HER). However, due to the catalytic inertness of the base surface and limited active sites, the HER performance of MoS2 has not yet reached the ideal state. Herein, we have successfully fabricated nanoflower-like MoS2 with the porous structure containing defects by doping with Co and P atoms with the hydrothermal method to increase the electron transfer rate, enhance electronic conductivity, and expose more active sites. The optimized Co, P-codoped MoS2 (Co, P-MoS2) possesses a superior catalytic performance to pristine MoS2 evidenced by a relatively lower overpotential (230 mV at 10 mA cm−2) and a very small Tafel slope (53 mV dec−1) with comparatively good stability in acidic media. Meanwhile, it is better than other MoS2-based catalysts in this work, owing to the synergistic effect caused by the codoping of Co and P atoms. In addition, the synthetic method of the material is simple; the experimental raw materials are cheap and easy to obtain, which provides the possibility for large-scale industrial hydrogen production; and it paves a new pathway for improving electrocatalytic performance by multi-atom doping which achieves complementary advantages. [ABSTRACT FROM AUTHOR]

There are various types of distributed generators (DGs) with different grid integration strategies. The transient characteristics of the fault currents provided by the DGs are different to those of conventional synchronous generators. In this paper, a distribution network with multi-type DGs is investigated, including consideration of DG low-voltage ride through (LVRT). The fault current characteristics of two typical DGs, i.e. an inverter-interfaced distributed generator (IIDG) and a doubly-fed induction generator (DFIG), are analyzed, considering the specific operation modes. Based on analysis of the fault characteristics, an equivalent model of the multi-type DGs under symmetrical/asymmetrical fault conditions is established. A fast-iterative fault calculation method for enhancing the calculation efficiency while avoiding local convergence is then proposed using an improved particle swarm optimization (PSO) algorithm. A simulation system of the distribution network with multi-type DGs is established in PSCAD/EMTDC. The simulation results validate the high accuracy and calculation efficiency of the proposed calculation method of the fault components. This can assist in the settings of the protection threshold. [ABSTRACT FROM AUTHOR]

The rapid recombination of electron-hole pairs in BiVO4 has limited its performance as a photocatalysis. In this paper, BiVO4 is combined with Cu2−xSe semiconductor to slow down the recombination process, and thus improve its photocatalytic activity. This is enabled by careful band structure design. The work function of Cu2−xSe is larger than that of BiVO4. Therefore, electrons flow to Cu2−xSe from BiVO4 after the composition. Accordingly, an inner field could be built, which facilitates the separation of electrons and holes. The experimental result shows that the photocatalytic efficiency of the 3 wt% Cu2−xSe/BiVO4 composite is 15.8 times than that of pure BiVO4. [ABSTRACT FROM AUTHOR]