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This study used the submerged arc discharge method (SADM) to produce metal fluid containing nanoparticles and submicron particles, whereby the energy focused by an electric arc was used to disintegrate silver (Ag) metal in deionized water (DW). No additional chemical substances were required throughout the process, which enabled production to be fast and straightforward. This study proposed using colorimetry to define the interrelation between concentration and nano Ag as well as the Ag ions (Ag+) within a nano silver colloid (NSC) of a specific dilution factor, involving ultraviolet-visible (UV-Vis) spectroscopy and the measuring of electrical conductivity. The results showed that Ag+ activity increased under various dilution conditions, displaying an upward trend in activity with an increase in the dilution factor. The absorption values of Ag+ and nanoparticles increased over time, and the Ag+ activity increased by up to a factor of two after its dilution. Therefore, the Ag+ and nanoparticles demonstrated an interdependence between each other.

Transformer excitation magnetizing curves (TEMC) reflect the dynamic operation characteristics of iron-core materials. Using numerical analysis and the waveform recording function of digital oscilloscopes, we developed a cost-effective method for determining the TEMC. This approach eliminates the need for conventional analog integrator circuits. To address the potential obstacles to the digital generation of TEMC—namely, curve offsets and curve transients—we proposed solutions involving Fourier filtering and determining the initial point of integration. The results indicate that the proposed approach yields results consistent with those of conventional analog integrator circuits and highlight its promise for applications in data processing. [ABSTRACT FROM AUTHOR]

This paper presents a practical and effective novel approach to solve the coordination problem caused by the curve intersection of overcurrent relays in subtransmission systems. Based on the IEEE and IEC standard characteristic curve equations of digital overcurrent relays, as well as the simulation curve equation for electromagnetic overcurrent relays, lever setting adjustment equations for a selected point on the characteristic curve is derived. Then, centered on the derived equations, a dedicated software program is developed to compute the corresponding relay lever setting with different tap value in order that, passing through the selected point, another curve with the new lever setting is chosen. Finally, assisting with the graphical capability of the commercial ASPEN OneLiner, the proposed fixed-point coordination curve adjustment procedure can completely eliminate the coordination curve intersections. In addition, an actual case of a subtransmission network in Taiwan Power Company is simulated to validate the feasibility of the technique proposed. Index Terms--Overcurrent relay, protection coordination, subtransmission system, sympathy trip.

This work presents a novel advanced methodology to accurately predict the earth leakage currents for analyzing the electrification railway systems with drain auto-transformers. The proposed methodology entails applying a decoupled technique to model the equivalent circuit while simultaneously considering the grounding network and the effects on mutual impedance between feeders. Also presented herein are several study cases, particularly with respect to how grounding resistance, span of auto-transformers, turn-ratio of auto-transformers, and location of ground faults influence the leakage currents. These study cases demonstrate that the computer program based on the proposed methodology can effectively analyze the leakage currents in the planning stage for developing railway systems.

This paper proposes the optimal planning of large passive-harmonic-filters set at high voltage level based on multi-type and multi-set of filters, from which, the types, set numbers, capacities and the important parameters of filters are well determined to satisfy the requirements of harmonic filtering and power factor. Four types of filters, namely single-tuned filter, second-order, third-order and C-type damped filters are selected for the planning. Firstly, the characteristics of filters are analyzed. The cost function and the constraints of filters and system are constructed for formulating the optimization problem of the planning of filters. Secondly, the simulated-annealing (SA) algorithm for searching optimal solution of planning of filters is developed. Finally, three cases of filter planning are presented to show that the superiority and availability of the SA algorithm and proposed planning results of filters. Index Terms--High Voltage, Large Capacity, Optimal Planning, Passive-Harmonic-Filter.

Electric Discharge Method (EDM) was used to prepare graphene in deionized water which CO2 had been dissolved in advance. According to law of mass conservation, the chemical equation of EDM was balanced to prove the component was graphene. Tyndall effect, ultraviolet-visible spectroscopy (UV-Vis), Zetasizer, Transmission Electron Microscope and Raman were used for the identification of graphene. Then the impact of CO2 concentration on graphene preparation was discussed. The results showed that carbon atoms assemble into forming graphene. And zeta potential of graphene was − 31.6 mV, which indicated good suspension of graphene. [ABSTRACT FROM AUTHOR]

Electric Discharge Method (EDM) was used to prepare graphene in deionized water which CO2 had been dissolved in advance. According to law of mass conservation, the chemical equation of EDM was balanced to prove the component was graphene. Tyndall effect, ultraviolet-visible spectroscopy (UV-Vis), Zetasizer, Transmission Electron Microscope and Raman were used for the identification of graphene. Then the impact of CO2 concentration on graphene preparation was discussed. The results showed that carbon atoms assemble into forming graphene. And zeta potential of graphene was − 31.6 mV, which indicated good suspension of graphene. [ABSTRACT FROM AUTHOR]

A strategy that combines electrochemical synthesis and photoredox catalysis was reported for the efficient synthesis of imines. This approach was demonstrated to be highly versatile in producing various types of imines, including symmetric and unsymmetric imines, by exploring the impact of different substituents on the benzene ring of the arylamine. Additionally, the method was specifically applied to modify N-terminal phenylalanine residues and was found to be successful in the photoelectrochemical cross-coupling reaction between NH 2 -Phe-OMe and aryl methylamines, leading to the synthesis of phenylalanine-containing imines. Therefore, this technique would present a convenient and efficient platform for synthesizing imines, with promising applications in chemical biology, drug development, and organic synthesis., (© 2023 Wiley-VCH GmbH.)