Automatic Current Sharing Mechanism in Two-phase Series Capacitor Buck DC-DC Converter (2-pscB)

In this chapter, we introduce the concept of the Inherited Automatic Current Sharing Mechanism (ACSM) in a two-phase series capacitor buck topology (2-pscB). This topology was introduced to power laptops as low-voltage and high-current Voltage Regulator Modules as well as non-isolated Point-of-Load converters (Vin < 12 V). To satisfy the converter stability, a state-space modeling technique of switching intervals coupled with parasitic component linearization is developed. Due to the series capacitor charging period miscalculation, the applicability of the ACSM of 2-pscB switching topology for high-power electronic applications is still very limited. Inserting a series capacitor between power switches of phase A increases loop parasitic inductance, introduces a time delay mismatch between the gate voltages of the two switches, and causes interference with the synchronization of the dead time between both phases of 2-pscB converters since the phase B has no series capacitor. This mismatch reduces the heat distribution efficiency and lifetime. As such, a complete model study delivered by the converter is required to design a robust controller. Driven to explore the series capacitor voltage feedback mechanism, frequency analysis of transfer functions, and filter behavior with experimental prototype examples (Vin < 120 V) have been presented for the first time to demonstrate the theoretical analysis. Obtained efficiency was up to 94.9% at full load

DNA from Plant leaf Extracts: A Review for Emerging and Promising Novel Green Corrosion Inhibitors.

With growing global awareness and concern for environmental protection through the use of less hazardous and environmentally-friendly extracts of plant origin, there has been a plethora of green corrosion inhibitors research with far reaching contributions to the science of corrosion prevention and control. Attention has increasingly turned towards green corrosion inhibitors, compounds of natural origin with anti-oxidant activity towards metals and their alloys. Green inhibitors have been investigated for their corrosion and adsorption properties with good results. The findings from these research works provide evidence of the adsorption behavior of green inhibitors which was confirmed by the adsorption isotherms that were proposed. Adsorption is the first step of any surface reaction and since corrosion is a surface phenomenon the effectiveness of green corrosion inhibitors is related to their ability to adsorb on metal surfaces. This review proposes the potential of plant dna as an emerging and promising novel inhibitor for mild steel. It begins with a list of plants that have been used in studies to determine corrosion inhibition properties and moves on to establish the adsorption behavior of bio macromolecules; protein, polysaccharides (chitosan) and dna. It reviews studies and investigation of dna interaction and adsorption on inorganic surfaces before focusing on the use of salmon (fish) sperm dna and calf thymus gland dna as green corrosion inhibitors for mild steel. It concludes that plant dna is a promising candidate for green corrosion inhibitor given the similarity between the plant and animal dna structure and function, and the fact that the use of plant is more environmentally sustainable than animal-based produc