Search

Plasma seed pretreatment is an important means to rapidly improve seed quality. The studies on plasma-generating devices suitable for continuous seed pretreatment at atmospheric pressure have been relatively limited. Gliding arc discharge can generate atmospheric pressure plasma at room temperature, which provides a new way to use plasma to treat seeds at ambient temperature and pressure. By analyzing the influence of structural characteristics, such as gliding arc electrode shape, discharge distance, and electrode opening angle on plasma distribution, a plasma seed treatment method based on negative pressure guidance was proposed, and the electrode structure was optimized. The results show that the reasonable matching of electrode structure parameters can improve the gliding arc guiding ability of the discharge electrode. Comparing the three electrode shapes, it was found that the triangular electrode had the best gliding arc guiding ability, and it had the potential to further increase the plasma size with the increase in the electrode size. The discharge distance and electrode opening angle had a significant impact on the gliding arc guiding ability of the discharge electrode. When the discharge distance was 15 mm and the electrode opening angle was 76°, the structure parameters of the plasma seed treatment electrode were matched with each other, and the best processing capacity was achieved. After 10 s of gliding arc plasma treatment with the optimized triangular electrode structure, the seed germination rate and germination index of Leymus chinensis ((Trin.) Tzvel) increased by 33.3% and 13.8%. This study provides a theoretical basis for the design and optimization of gliding arc electrode structures and serves as a reference for the research and development of plasma generators for continuous seed treatment at atmospheric pressure.

To analyze the interaction between the surface soil and the soil-contacting component (65 Mn) in the camellia oleifera forest planting area in Changsha City, Hunan, China, in this study, we conducted discrete element calibration using physical and simulation tests. The chosen contact model was Hertz–Mindlin with JKR cohesion, with the soil repose angle as the response variable. The repose angle of the soil was determined to be 36.03° based on the physical tests. The significant influencing factors of the repose angle determined based on the Plackett–Burman test were the soil–soil recovery coefficient, soil–soil rolling friction coefficient, soil-65 Mn static friction coefficient, and surface energy of soil for the JKR model. A regression model for the repose angle was developed using the Box–Behnken response surface optimization method to identify the best parameter combination. The optimal parameter combination for the JKR model was determined as follows: surface energy of soil: 0.400, soil–soil rolling friction coefficient: 0.040, soil-65 Mn static friction coefficient: 0.404, and soil–soil recovery coefficient: 0.522. The calibrated discrete element parameters were validated through experiments on the repose angle and steel rod insertion. The results indicated that the relative errors obtained from the two verification methods were 2.44% and 1.71%, respectively. This research offers fundamental insights for understanding the interaction between soil and soil-contacting components and optimizing their design.

To investigate the impact of different cutter structures on the crushing effect of forage stalks at various rotational speeds, this study designed five types of crushing cutters. The effects of cutter structure and rotational speed on the crushing effect of the forage crusher were examined using the discrete element method, a single-factor test. An orthogonal test was conducted, with the percentage of bond breakage as the evaluation index, and tool type and tool speed as influencing factors. The results of the orthogonal test were analyzed using range analysis. The findings revealed that the quality of alfalfa stalk crushing varied depending on the crushing structure and rotational speed. Within a certain rotational speed range, the crushing effect improved as the rotational speed increased. However, beyond a certain value, the improvement in the crushing effect became slower. Notably, the hob-type crushing structure exhibited the best crushing effect at 2400 r/min.

Pre-sowing treatment of seeds by plasma can improve seed vigor and promote seed germination and growth. To solve the problems of low processing volume and uneven treatment in plasma seed treatment devices, according to the process scheme of medium-blocking discharge plasma seed treatment, a medium-blocking discharge vibration-uniform material plasma seed treatment device was designed, the structure and working principle of the vibration-uniform material device were systematically analyzed, and the mathematical model of seed force was established. According to electromagnetic vibration theory, the seed sorting and conveying principles were analyzed in the lower trough, and the relevant parameters were selected and calculated. Using EDEM discrete element simulation software, a numerical simulation of alfalfa seed feeding and vibration-uniform material process was carried out. A three-factor, three-level orthogonal test was established. The results showed that the vibration amplitude and groove shape significantly affected the coefficient of variation of seed uniformity on the groove during the seed feeding and vibration-uniform material processes, and the groove wheel speed had a certain effect on the coefficient of variation of uniformity. The main order of factors affecting the uniformity of seed spreading was vibration amplitude B > notch shape C > speed A. The optimal speed was 35 r/min, the optimal notch shape was circular, and the optimal vibration amplitude was 0.55 mm.