Archimedes Optimization Algorithm Based Selective Harmonic Elimination in a Cascaded H-Bridge Multilevel Inverter

This paper presents the Archimedes optimization algorithm to eliminate selective harmonics in a cascaded H-bridge (CHB) multilevel inverter (MLI). The foremost objective of the selective harmonic elimination (SHE) is to eliminate lower order harmonics by finding the optimal switching angle combination which minimizes the objective function containing Total Harmonic Distortion (THD) and other specific harmonic terms. Consequently, the THD is also reduced. In this study, a recently proposed metaheuristic technique named the Archimedes optimization algorithm (AOA) is used to determine the optimal angles corresponding to the 5, 7 and 9 level CHB-MLI. AOA involves equations related to a physical law, the Archimedes Principle. It is based on the idea of a buoyant force acting upward on a body or object that is partially or completely submerged in a fluid, and the upward force is related to the weight of the fluid displaced. This optimization technique has been implemented on CHB-MLI to generate various level outputs, simulated on MATLAB™ R2021a version environment software. The simulation results reveal that AOA is a high-performance optimization technique in terms of convergence speed and exploitation-exploration balance and is well-suited to the solution of the SHE problem. Furthermore, the laboratory validated the simulation result on a hardware setup using DSP-TMS320F28379D.

The interactive computer simulation and learning activity for facilitating students’ conceptual understanding on the buoyant force through the CoSci learning platform

Learning science, especially in the physics field, there are many varieties of invisible and abstract phenomena that are hard and difficult for students to observe and learn. One of the tools that can help students to understand those phenomena in a better way is computer simulations. The computer simulations are usually used in both on-site classroom and on-line learning platforms. Learning in the COVID-19 pandemic era at present, the computer simulations are very important for helping students to understand the physics concept. Interactive computer simulation can be considered as one of the effective methods of facilitating inquiry learning in science, as it allows students to experience the scientific inquiry process and facilitates students to understand an abstract conception and to understand the relationship between variables of invisible phenomena more clearly in reasonable ways. This study aimed to develop the interactive computer simulation and learning activity for enhancing students’ conceptual understanding of the buoyant force on the CoSci learning platform. Totally eighteen participants were studied in the twelfth grade in science classrooms of a university-affiliated school project (SCiUS), Khon Kaen University, Thailand, in 2019. The learning activity was developed based on students’ alternative concepts and used to facilitate students’ conceptual understanding of the buoyant force. There were six basic concepts related to the buoyant force constructed based on the predict-observe-explain strategy (POE) with the interactive computer simulation (i.e., the CoSci learning platform) in the learning activity. The learning activity on the CoSci learning platform consisted of eight pie charts such as 1) main question pie chart, 2) density pie chart, 3) water level pie chart, 4) volume pie chart, 5) mass pie chart, 6) weight pie chart, 7) submerged depth pie chart, and 8) answer pie chart. There were six interactive computer simulations used in this research including 1) density simulation, 2) water level simulation, 3) volume simulation, 4) mass simulation, 5) submerged depth simulation, and 6) weight simulation. All of these simulations were developed on the CoSci learning platform (https://cosci.tw/). The findings showed that 72% of students performed better in the post-test scores than in the pre-test score in all six basic concepts related to the buoyant force after learning buoyant force on the CoSci platform. Furthermore, the most difficulty in changing misconception in learning of the buoyant force was the concept related to the mass of the object.

Non-Coaxially Rotating Motion in Casson Martial along with Temperature and Concentration Gradients via First-Order Chemical Reaction

The effect of non-coaxial rotation on the transport of mass subjected to first-order chemical reaction is studied analytically. The effects of thermal radiation, buoyancy, constructive and destructive chemical reactions along with Casson fluid in rotating frame are discussed. Time evolution of primary and secondary velocities, energy and solute particles are analyzed. The behavior of flow under the variation of intensity of magnetic field is also investigated. Evolutionary behavior of primary velocity is opposite to the evolutionary behavior of secondary velocity. The impact of buoyant force on primary velocity is opposite to the role of buoyant force on the secondary velocity. The evolutionary behavior of temperature is also examined and a remarkable enhancement in temperature is noticed. Thermal radiation causes the fluid to be cooled down as heat energy is escaped by thermal radiation. Evolutionary behavior of concentration is also analyzed and an increasing of concentration versus time is noted. Destructive chemical reaction results a remarkable reduction in the concentration and vice versa for generative chemical reaction.

Design and Analysis of a Helium-Assisted Hybrid Drone for Flight Time Enhancement

In this paper, a new design of a helium-assisted hybrid drone is proposed for flight time enhancement. As is widely known, most of the drones with a VTOL (vertical take-off and landing) feature have a short operation time, limiting their capability to carry out sustainable operations for the given missions. Thus, with the clear goal of enhancing the flight time, this study aims to develop a hybrid drone system, where a helium balloon is used to provide a lifting force for this purpose. The proposed design for the hybrid drone has several benefits including easiness to manufacture and relatively small size when compared to other types of hybrid drones. Various analyses are conducted for the design of the hybrid drone system including the balloon shape and size, buoyant force, flight time, and connector design. Since stability and performance are one of the most important issues for the new design, the pole location analysis is conducted based on the control theory. This rigorous analysis provides that the proposed hybrid drone design is stable as well as robust against swinging motions. To validate the effectiveness of the proposed design and flight time enhancement, simulations were conducted and experimental results are also provided using the manufactured hybrid drone system. Through the real experiments, it is proved that the hybrid drone can increase the flight time more than 2.5 times while guaranteeing stable motions.

Design of Thermally Constrained High-Frequency Induction Heating System

One of the most prominent application areas of induction heating principle is for sealing of caps of plastic and glass containers. It is increasingly being used to seal containers with extremely wide range industrial products. The process ambience around the controller for sealing of bottles containing different types of products could be different. Such prospects, often, could act as constraints for design of power controllers. Dust prone environment prevailing in processes such as for sealing nutraceuticals, coffee, a few pharma products, etc. recommends use of air-tight enclosure. It does not have any ventilation, even the natural air movement inside or the free convection is restricted. This article proposes that the internal convection could still be made effective by creating requisite buoyant force where both power converter topology and component engineering could play important roles. The topology should optimally reduce the power loss and surface temperature of components should be high. The proposed idea has been validated by designing a zero-ventilated 1.5 kW, 50 kHz induction heating system that includes the induction coil head.

Optimal Incorporation of Photovoltaic Energy and Battery Energy Storage Systems in Distribution Networks Considering Uncertainties of Demand and Generation

In this paper, the Archimedes optimization algorithm (AOA) is applied as a recent metaheuristic optimization algorithm to reduce energy losses and capture the size of incorporating a battery energy storage system (BESS) and photovoltaics (PV) within a distribution system. AOA is designed with revelation from Archimedes’ principle, an impressive physics law. AOA mimics the attitude of buoyant force applied upward on an object, partially or entirely dipped in liquid, which is relative to the weight of the dislodged liquid. Furthermore, the developed algorithm is evolved for sizing several PVs and BESSs considering the changing demand over time and the probability generation. The studied IEEE 69-bus distribution network system has different types of the load, such as residential, industrial, and commercial loads. The simulation results indicate the robustness of the proposed algorithm for computing the best size of multiple PVs and BESSs with a significant reduction in the power system losses. Additionally, the AOA algorithm has an efficient balancing between the exploration and exploitation phases to avoid the local solutions and go to the best global solutions, compared with other studied algorithms.

Volcanic eruptions are triggered in static dilatational strain fields generated by large earthquakes

Although data catalog analyses have confirmed that volcanic eruptions are triggered by large earthquakes, the triggering mechanism has been under discussion for many decades. In the present study, recent earthquake and volcanic data from the past 35–55 years were analyzed, and it was demonstrated for the first time that the likelihood of new eruptions increases two to three times in the 5–10 years following large earthquakes for volcanoes where the generated static dilatational strain exceeds 0.5 µ, which may, for example, activate gas bubble growth and thereby generate a buoyant force in the magma. In contrast, the eruption likelihood does not increase for volcanoes that are subjected to strong ground motion alone, which affect the magma system and volcanic edifice. These results indicate that we can evaluate the likelihood of triggered eruptions and prepare for new eruptions when a large earthquake occurs.

Powerful Material Technology Removes Barriers

Strengthening materials through grain refinement often results in reduced ductility necessitating means to augment their elongation to failure for engineering applications. Grain boundary engineering (GBE), encompassing novel thermo-mechanical processing has shown promise of simultaneously enhancing both strength and ductility of materials and fracture behavior, especially with low stacking fault energy materials. The ultrahigh strength and reasonable ductility originate from dislocations being effectively blocked at the nano-twinned boundaries resulting in dislocation accumulation and entanglement. This necessitates the careful design of alloys and nano-composites, an effective harnessing of these unique sub-micron features to the benefit of engineering downhole tools for strategic applications. Enabled by these novel material developments, here we present two such articles for the unconventionals. First, a frangible barrier to abet placement of casings and liners through trapping an air column below the barrier while supporting a fluid column in the casing above, providing an up-thrust, a buoyant force that significantly reduces drag and lateral casing weight during placement. This is a viable concept because "shales don't kick". Second is the unmet need for a clean perforating tunnel allowing reduced fluid friction thus better reservoir connectivity. This has been achieved through the development of a novel shape charge with a reactive liner which during the detonation event, additionally generates reactive metallic glassy phase(s) and high entropy alloy complex(s) and their segregation in the deposited jet debris that lines the perf-tunnel. During flowback, reaction with aqueous fluids selectively etch these phases and stimulates the disintegration of the impervious skin on the perf-tunnel into fine particulates subsequently removing them, leaving behind a clear, clean tunnel.

Design of Thermally Constrained High-Frequency Induction Heating System

One of the most prominent application areas of induction heating principle is for sealing of caps of plastic and glass containers. It is increasingly being used to seal containers with extremely wide range industrial products. The process ambience around the controller for sealing of bottles containing different types of products could be different. Such prospects, often, could act as constraints for design of power controllers. Dust prone environment prevailing in processes such as for sealing nutraceuticals, coffee, a few pharma products, etc. recommends use of air-tight enclosure. It does not have any ventilation, even the natural air movement inside or the free convection is restricted. This article proposes that the internal convection could still be made effective by creating requisite buoyant force where both power converter topology and component engineering could play important roles. The topology should optimally reduce the power loss and surface temperature of components should be high. The proposed idea has been validated by designing a zero-ventilated 1.5 kW, 50 kHz induction heating system that includes the induction coil head.

Design of Thermally Constrained High-Frequency Induction Heating System

One of the most prominent application areas of induction heating principle is for sealing of caps of plastic and glass containers. It is increasingly being used to seal containers with extremely wide range industrial products. The process ambience around the controller for sealing of bottles containing different types of products could be different. Such prospects, often, could act as constraints for design of power controllers. Dust prone environment prevailing in processes such as for sealing nutraceuticals, coffee, a few pharma products, etc. recommends use of air-tight enclosure. It does not have any ventilation, even the natural air movement inside or the free convection is restricted. This article proposes that the internal convection could still be made effective by creating requisite buoyant force where both power converter topology and component engineering could play important roles. The topology should optimally reduce the power loss and surface temperature of components should be high. The proposed idea has been validated by designing a zero-ventilated 1.5 kW, 50 kHz induction heating system that includes the induction coil head.