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The food industry is in a constant search for new technologies to improve the commercial sterilization process of agricultural commodities. Plasma treatment may offer a novel and efficient method for pesticide removal from agricultural product surfaces. To study the proposed technique of plasma food treatment, the degradation behavior of diazinon insecticide by air-dielectric barrier discharge (DBD) plasma was investigated. The authors studied the effect of different plasma powers and treatment times on pesticide concentration in liquid form and coated on the surface of cucumbers, where the diazinon residue was analyzed with mass spectroscopy gas chromatography. Our results suggest that atmospheric pressure air-DBD plasma is potentially effective for the degradation of diazinon insecticide, and mainly depends on related operating parameters, including plasma treatment time, discharge power, and pesticide concentrations. Based on the interaction between reactive oxygen species and electrons in the plasma with the diazinon molecule, two degradation pathway of diazinon during plasma treatment are proposed. It was also found that produced organophosphate pesticides are harmless and less hazardous compounds than diazinon.

Medium Voltage Load Break Switches (MV-LBS) should pass fault current while closing and be able to re-open for the next operation. Replacing SF6 as a high impact greenhouse insulating gas with air, makes the switch design more challenging because of the higher prestrike arcing time and energy dissipation between contacts which leads to more contact surfaces' erosion and even higher possibility of welding. In this paper, a synthetic test circuit is used to emulate stresses applied to MV-LBS during the making of short-circuit currents. Since there are difficulties in accurate direct measurement of arc voltage because of the inherent response of the measurement system, an alternative method using Optical Emission Spectroscopy (OES) is proposed. OES measures the pre-strike arc temperature distribution profile close to the cathode surface at a test voltage of 18 kV and a making current of 17 kA. The arc electrical characterization is achieved using obtained spectroscopy results, Lowke's model, and thermal air plasma transport properties. A maximum arc temperature of 12500 K while the arc moves from the lower part of the cathode to the center, arc voltage of 30-58 V, and dissipated energy of 79-87 J are calculated for the pre-strike arc considering the impact of copper evaporated from the contact surfaces. Different arc behavior is observed in closing the contacts compared to free-burning arcs, which indicates gas flow blowing the arc caused by the contact movement. This investigation could be used for a better understanding of switching behavior and efficient control of the operation.

Replacing SF6, the most potent greenhouse gas, with an alternative gas is a challenge faced by medium-voltage load break switches (MV-LBS). Air is a possible alternative, but there are some challenges regarding low dielectric strength leading to high arcing time and dissipated energy. Therefore, understanding the switching processes for both interruption and making operations in air MV-LBS is crucial to designing efficient compact switchgear. This work focuses on making operations in air MV-LBS. A synthetic test circuit and a model switch are designed based on the standards to simulate making operations under fault conditions similar to a real test. The test condition is set to achieve high prestrike arcing time and energy. The results show that the most destructive impact of the making short-circuit current occurs in the first half-cycle of the load current when the pre-strike arc is formed. With an average short-circuit current with a peak of 22 kA and a breakdown voltage of 20 kV, the switch failed to re-open due to the arcing contacts welding after four successive making operations without main contacts and seven successive operations with main contacts. It has been shown that the total arcing contact mass loss occurs mainly during the pre-arcing time. Increasing the closing speed could be a possible solution to minimize the impact of arcing. Index Terms-medium voltage (MV), load break switch (LBS), making operations, contacts erosion, arcing contacts, main contacts, arc erosion.

Energy dissipation during pre-strike arc is the critical factor for electrical contacts erosion and welding in medium voltage load break switches. Using air-filled devices as an alternative to SF6, makes the switch environmentally friendly, but leads to a more challenging process due to a higher pre-strike arcing time between contacts. Therefore, understanding the erosion process of electrical contacts is crucial to improve the switch lifetime. Determination of contacts surface evaporation by optical emission spectroscopy is one of the most precise methods to investigate the pre-strike arc interface with the contacts. In this paper, the temporal and spatial profiles of copper and tungsten emitted species during pre-strike arc are presented. For this purpose, a circuit consisting of a synthetic DC high voltage part is used to initiate the arc. The temporal evolution of CuI, CuII, and WI shows evaporation of the cathode and the anode surfaces during the pre-strike arc, and the spatial profiles show an inhomogeneous distribution of the vapors alongside the arc root.