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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]

Paralleled pulse-forming units (PFUs) with different triggering delays might be a paramagnetic way for generating flat-topped current wave for electromagnetic launch. Many researchers have reported that multiple capacitive storage PFUs were implemented such current waves in laboratories. However, due to its low energy density, the applications of the capacitive pulsed-power supplies are limited. Since the inductor has advantages in energy density, the inductor pulsed-power supply becomes one of the hottest topics recently. The slow transfer of energy through capacitive hybrid meat grinder with inverse current commutation with semiconductor devices proposed by Tsinghua University has demonstrated its advantage and applicability recently. Using this kind of topology, this paper proposes the design of an inductive storage PFU with a stored energy of 100-kJ. The maximum load current reaches to 50 kA and its pulsewidth is at least 5 ms. The optimized inductive storage PFU shows superiority in contrast to the capacitive storage PFU with the same energy. This paper offers the theoretical analysis and the testing foundation for investigating the inductor pulsed-power supply with higher energy. [ABSTRACT FROM PUBLISHER]

By applying the principle of inverse current commutation with semiconductor (ICCOS) devices in a slow transfer of energy through capacitive hybrid (STRETCH) meat grinder system, a novel circuit topology called STRETCH meat grinder with ICCOS was proposed by the Tsinghua University in 2013. It can not only raise the amplitude of the opening current, but also reduce the cost of the STRETCH meat grinder circuit obviously by replacing the integrated gate-commutated thyristor (IGCT) with thyristor. This paper discusses the overall design, system implementation, and testing results of a STRETCH meat grinder with ICCOS system with roughly 1-kJ inductive energy. The load is a spiral coil with 1.4- \textm\Omega resistance and 1.4- \mu \textH inductance. With closed-loop control strategy, the system detects the charging current of the inductors. When it reaches the designated value, the triggering signal for ICCOS is delivered and after the predefined delay time, the triggering signal for discharging the voltage on the pulse-forming capacitor is delivered. The current of the inductors and the load are measured by Rogowski coils. The opening current is 1 kA and the maximum load current is close to 4 kA. All the voltages on the switches are lower than 1 kV. The experimental results are consistent with the simulated ones, which verified the correctness of the theoretical analysis and proved the applicability of the STRETCH meat grinder with ICCOS for larger energy level. [ABSTRACT FROM PUBLISHER]

Slow transfer of energy through capacitive hybrid (STRETCH) meat grinder circuit, which was proposed by the Institute for Advanced Technology, added a capacitor into the traditional meat grinder circuit. Even though its energy density is slightly less than the corresponding pure inductance system, it can reduce the voltage across the opening switch and maintain the high multiplication factor of the opening current. The performance of the STRETCH meat grinder circuit depends on multiple parameters. The inductance ratio ( n=L1 / L2) and the capacitance (C) are the two vital factors, which have a crucial influence on the system performance, such as the voltage over the opening switch ( V_{\rm Sopm}) , the current multiplication factor ( m$ ), and the ratio of the maximum capacitive energy over the total inductive energy ( $\eta )$ . Thorough studies have been carried out in this paper on the relationship between the above two factors and the three performance criteria. This paper also discusses and analyzes the chosen of the key parameters ( $n$ and $C$ ) for a single-stage STRETCH meat grinder with 2-mH total inductance, which is made up of two serial coils with 0.95 coupling factor. The opening current of the main switch is 1 kA, which constitutes a 1-kJ inductive pulsed-power supply. It fully takes the advantage of the STRETCH meat grinder topology, intensifies the study of the inductive pulsed-power supply with higher energies, and is easy to be utilized for practical application. [ABSTRACT FROM PUBLISHER]

Structural parameters directly affect the energy density and the total resistance of the inductors used in inductive pulse power supply (IPPS). This paper elaborates the relationship between the structural parameters and electrical performances of the inductors used in IPPS and set up the inductors for the experiment in slow transfer of energy through capacitive hybrid meat grinder circuit using air-core flat spirals of strip coil. Then we compile a program that can obtain the structural parameters of the inductors that have the highest energy density under the condition of given charging and discharging currents as well as inductances in the primary and secondary sides. The calculation results of the program are analyzed and verified by the measured values of the real inductors. At the end, on the condition of a constant current density, we put forward a rule that along with the increase in the system energy, the energy density of the IPPS became higher and the resistance of the inductors became lower. [ABSTRACT FROM PUBLISHER]