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Bismuth oxide (Bi2O3) and Bi2O3–supported Kaolin were synthesized using household microwave–assisted methods (350 W, 5 min), with catalyst characteristics analyzed. XRD patterns confirmed the monoclinic structure of Bi2O3. Incorporating 20%w/w Kaolin increased the specific surface area of Bi2O3 from 6.2879 to 16.1345 m2/g, observed in FESEM images showing a hierarchical flower-like morphology resembling French fries alongside Kaolin plates. XRF analysis identified elements in Kaolin contributing to self–doping in band structure of Bi2O3, reducing its band gap and PL intensity. Kaolin/Bi2O3 composites demonstrated enhanced photocatalytic degradation of tetracycline (TC) under visible light, attributed to Bi2O3-generated radicals and increased surface area. The composite photocatalyst can be recycled up to three times. This research not only enhances the photocatalytic activity of Bi2O3 but also increases the value of a local waste material, Kaolin clay. Such enhancements could potentially extend to other metal oxides and abundant waste materials within the country. [ABSTRACT FROM AUTHOR]

This study developed a grid-connected biogas power generation system for a rural community using a 3-phase 2.2 kW squirrel-cage induction machine as the self-excited induction generator. The generator was driven by a 196 cc single-cylinder spark-ignition engine fueled by biogas. We developed a back-to-back converter that consists of a 3-phase PWM rectifier as the generator-side converter and a single-phase LCL-filtered grid-connected inverter. The generator-side converter transferred the active power to the grid-side converter and supplied the reactive power control back to the generator. The notch filter-based bus voltage control on the generator side mitigated the inter-harmonics in the generator current. The injected grid current complied with the IEEE 1547 standard because of the multi-frequency unbalanced synchronous reference frame control. The proposed system was validated with biogas produced from pig manure at a pig farm in central Thailand, which found a maximum output of 1.2 kW with a thermal system efficiency of 10.7%. The proposed system was scheduled to operate at 1.2 kW for 8 h per day with a levelized cost of 0.07 US$/kWh, 42% cheaper than the retail electricity price, and a payback period of 2.76 years. The proposed system is suitable for a farm with a minimum of 34 pigs. [ABSTRACT FROM AUTHOR]

This research investigated the increases of the voltage profile on the Provincial Electricity Authority (PEA)'s low voltage (LV) network due to the solar photovoltaic (PV) penetration. This study proposed the solution to maintain the voltage profile within the PEA's standard limitation by using battery energy storage system (BESS) application. The algorithm using bisection method to figure out the optimal size and location of BESS was examined and simulated in different scenarios such as summer/winter and weekend/weekday behaviors. Furthermore, the allocation of a battery in various locations was also considered. DIgSILENT power factory with DPL script and Python are the tools used to cover diverse scenario cases. The results showed that the best practice of how to implement BESS to solve the voltage rise problem was the BESS installation at the distribution transformer and the BESS installation separately at the end of each feeder near the loads. However, the optimal size of BESS installation at the distribution transformer was almost double that of installation at the end of each feeder. [ABSTRACT FROM AUTHOR]

This article reports an investigation into ferrite and nanocrystalline materials for the medium-frequency transformer of a dual active bridge DC-DC converter, which plays a key role in the converter's efficiency and power density. E65 MnZn ferrite cores and toroidal and cut nanocrystalline cores are selected for the construction of 20-kHz transformers. Transformer performance is evaluated with a 1.1-kW (42–54 V)/400 V dual active bridge DC-DC converter with single-phase shift and extended phase shift modulations. The experimental results indicate that the toroidal nanocrystalline transformer had the best performance with an efficiency range of 98.5–99.2% and power density of 12 W/cm3, whereas the cut-core nanocrystalline transformer had an efficiency range of 98.4–99.1% with a power density of 9 W/cm3, and the ferrite transformer had an efficiency range of 97.6–98.8% with a power density of 6 W/cm3. A small mismatch in the circuit parameters is found to cause saturation in the nanocrystalline toroidal core, due to its high permeability. The analytical and experimental results suggest that cut nanocrystalline cores are suitable for the dual active bridge DC-DC converter transformers with switching frequencies up to 100 kHz. [ABSTRACT FROM AUTHOR]