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Mulch film has provided significant convenience for agricultural development. However, its stable physical and chemical properties make it challenging to manage under natural conditions, potentially posing a serious environmental threat if mishandled. This study investigates the influence of various experimental factors on the degradation of agricultural film using low-temperature plasma degradation technology. A self-made needle-plate electrode structure was employed to treat polyethylene film with a high-frequency AC voltage. The study analyzesd the effects of input power, discharge time, electrode number, and air circulation on mulch film degradation. Changes in mulch quality, Raman spectrum, scanning electron microscope observations, and relative molecular mass were compared before and after treatment. The results revealed a 2.6-fold increase in mulch film degradation efficiency when the input power rised from 26 W to 80 W. While increasing input power enhanced high-energy electrons and active substances in the reaction space, energy efficiency did not proportionally increase with the degradation rate. At 51 W input power, the energy efficiency reached a maximum of 58.82 μg/(W·h). The number of needle tips influences plasma uniformity and input power, impacting film degradation efficiency. As the number of needle electrodes increases, film degradation efficiency initially decreased from 3.49% to 2.1%, then rised to 3.57%. Prolonged discharge time made the molecular chain structure more vulnerable to plasma attack and breakage. Additionally, air fluidity affects ozone concentration in the reactor, with higher concentrations in a closed environment at low input power. Increasing the input power to 80 W results in higher ozone concentration with good air fluidity, aiding in improving mulch film degradation efficiency.

The magnetic fluid seal (MFS) is a new type of sealing method that offers the advantages of no leakage and low wear. Hence, it is widely used in rotary seals in coal, chemical, and electric power fields. However, at high speeds, the degradation and even failure of the sealing performance severely limits the application of MFS in engineering. Therefore, this study designed a combined sealing device comprising a double screw seal and MFS and optimized the pressure resistance of the screw seal using an orthogonal test in combination with the response surface optimization method. Thus, the pressure resistance could be raised to 3.1 times that before optimization. The effect of the sealing gap on the sealing pressure of the MFS was analyzed by numerical simulation, and an optimal sealing gap value of 0.2 mm was obtained. The results of the verification test showed that the performance of the combined seal was significantly better than that of MFS alone. When sealing liquids, the pressure resistance of the combined seal reached 3.3 times that of the MFS at 3000 rpm, which indicates the application potential of MFS in high-speed working conditions. [ABSTRACT FROM AUTHOR]