ABSTRACT
A rapid, high voltage capacitor charging power supply (CCPS) based on a third order resonant converter topology has been proposed, analyzed, and simulated using the PSpice software, and as a proof of concept, a prototype of the 6.0 kV, 6.0 A CCPS is also developed. High charging power, low resonant current, and high pulse repetition rate were targeted in the design. In this paper, ac analysis for the calculation of impedance and resonant frequency, and frequency dependence on current gain, and the steady state analysis of the proposed scheme have been studied and presented. The performance is analyzed by simulating the circuit for two values of load capacitances. The simulation and prototype results show linear charging of the load for both values of load capacitances. The charging times of 1.47 and 0.97 ms have been achieved for load capacitances of 1.5 and 1.0 µF, respectively. The performance of the LLC topology has been compared with a conventionally used series resonant scheme. A high charging power of 18.4 kJ/s has been achieved. The topology shows a faster charging rate by â¼36% in comparison with the series LC resonant topology. The results of the analysis match with the simulation and prototype results, which confirms that the proposed scheme is suitable for rapid and reliable CCPS applications.
ABSTRACT
BACKGROUND: The rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) is a cosmopolitan pest of stored cereal grains and other commodities globally. Infestations caused by S. oryzae makes grains unsuitable for consumption, processing, and export. Deltamethrin, a synthetic pyrethroid insecticide, is widely used in major grain storages in India as a prophylactic treatment to control this pest. However, recurrent use of this insecticide had led to genetic resistance in S. oryzae, questioning its ongoing use at the current recommended concentration. RESULTS: Dose response analysis of resistant (Delta-R) and susceptible (Lab-S) strains of S. oryzae collected from grain storages across southern India, revealed that Delta-R was 134-fold more resistant than the Lab-S at median lethal concentration (LC50 ). A concentration of 180 ppm over 48 h effectively discriminated 16 resistant field populations from Lab-S with per cent resistance ranging from 8.72% to 75.86%. Exposing all the resistant populations to 1000 ppm over 48 h identified 12 populations with strongly resistant individuals and confirmed the existence of two distinct resistance phenotypes, 'weak' and 'strong' in S. oryzae. Furthermore, sequence analysis of the voltage-gated sodium channel (vgsc) gene in Delta-R identified a single target site mutation, T929I conferring resistance in S. oryzae. CAPS (Cleaved Amplified Polymorphic Sequence) marker analysis of this allele confirmed that frequency of resistance is high (up to 0.96) supporting the results of phenotypic analysis. CONCLUSION: Both phenotype and molecular marker analyses clearly demonstrated that deltamethrin at 180 and 1000 ppm can be used to discriminate weakly and strongly resistant populations in S. oryzae, respectively. Resistance diagnostics based on the mutation, T929I, supports our phenotypic data and indicates that resistance to deltamethrin in S. oryzae is prevalent in southern parts of India, stressing the need to identify a synergist or suitable alternatives. © 2021 Society of Chemical Industry.
