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The electrochemical nitrate reduction reaction (e‐NITRR) process based on plasma has become a potential technology for commercial large‐scale green ammonia synthesis. This work emphasized the prominent influence of operating parameters on e‐NITRR through the combination of experiments and simulations in an electrocatalytic flow cell reactor. An integrated model was developed and the non‐linear functions between operating conditions and exchange current density were obtained by optimization fitting. The average relative error of experiments and simulations was <5%, which can provide solutions for the design of reactor structures and optimization of process parameters. Besides, the results also showed that the tandem steps of NO3− → NO2− and NO2− → NH3 were, respectively, controlled by mass transfer and electrochemical kinetics at low electrolyte flow rate, and this characteristic makes the increase in electrode dimensions have the opposite effect on the formation rate of NO2− and NH3. [ABSTRACT FROM AUTHOR]

Hydrological processes play important roles in soil erosion processes of the hillslopes. This study was conducted to investigate the hydrological processes and the associated erosional responses on the purple soil slope. Based on a comprehensive survey of the Wangjiaqiao watershed in the Three Gorges Reservoir, four typical slope gradients (5°, 10°, 15°and 20°) were applied to five rainfall intensities (0.6, 1.1, 1.61, 2.12 and 2.54 mm·min-1). The results showed that both surface and subsurface runoff varied greatly depending on the rainfall intensity and slope gradient. Surface runoff volume was 48.1 to 280.1 times of that for subsurface runoff. The critical slope gradient was about 10°. The sediment yield rate increased with increases in both rainfall intensity and slope gradient, while the effect of rainfall intensity on the sediment yield rate was greater than slope gradient. There was a good linear relationship between sediment yield rate and Reynolds numbers, flow velocity and stream power, while Froude numbers, Darcy-Weisbach and Manning friction coefficients were not good hydraulic indicators of the sediment yield rate of purple soil erosion. Among the three good indicators (Re, v and w), stream power was the best predictor of sediment yield rate (R2 = 0.884). Finally, based on the power regression relationship between sediment yield rate, runoff rate, slope gradient and rainfall intensity, an erosion model was proposed to predict the purple soil erosion (R2 = 0.897). The results can help us to understand the relationship between flow hydraulics and sediment generation of slope erosion and offer useful data for the building of erosion model in purple soil.

Due to the adjustment of the Chinese industrial structure in recent years, the coal industries are facing a sluggish market environment. Therefore, it is important to study the product specification prediction and economic benefit maximization prediction of coal preparation plants. First, the washability data and distribution curve models were used to calculate the quantity and quality index of the products of the shallow slot heavy medium separator, the heavy medium cyclone, and the spiral separator, respectively. A gravity separation prediction model was built and the average fitting error of the model was 2.89%. Second, the calorific value – (ash and sulfur) model was built, in which SPSS was used to eliminate abnormal points. A mathematical model of the price of clean coal – calorific value was built. Finally, a genetic algorithm was used to optimize each sorting process to find the best sorting density of each sorting system: the result of the shallow slot heavy medium separator was 1.72 g/cm3, that of the heavy medium cyclone was 1.99 g/cm3, and the result of the spiral separator was 1.86 g/cm3. The maximum sales revenue of raw coal per ton from the economic benefit maximization prediction model was 379.79 yuan. The models provided forward-looking guidance for the related adjustments of production. [ABSTRACT FROM AUTHOR]