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Full-Text Articles in Engineering

Analysis Of Miniaturized, Circularly Polarized Antennas For Bidirectional Propagation, Mason C. Moore Jan 2021

Analysis Of Miniaturized, Circularly Polarized Antennas For Bidirectional Propagation, Mason C. Moore

Electronic Theses and Dissertations

Size reduction is necessary to fit the recent demand for small sized communication systems in consumer electronics. Wireless communication systems rely on antennas for long range transmission of signals, so size reduced antennas have been sought after in recent years. Also, not many antennas are designed for use in bidirectional scenarios like subways, tunnels, bridges, etc. Three sized reduced antennas with circular polarization are presented for use in bidirectional communication systems. An electrically small pattern reconfigurable array, an electrically small two-sided printed cross dipole, and a size reduced printed wideband antenna are introduced within this thesis. All antennas’ results are …


Quality Assurance Of Lightweight Structures Via Phase-Based Motion Estimation, Ikenna E. Ifekaonwu Jan 2021

Quality Assurance Of Lightweight Structures Via Phase-Based Motion Estimation, Ikenna E. Ifekaonwu

Electronic Theses and Dissertations

In recent years, lightweight structures have become mature and adopted in various applications. The importance of quality assurance cannot be overemphasized hence extensive research has been conducted to assess the quality of lightweight structures. This study investigates a novel process that exploits motion magnification to investigate the damage characteristics of lightweight mission-critical parts. The goal is to assure the structural integrity of 3D printed structures and composite structures by determining the inherent defects present in the part by exploiting their vibration characteristics. The minuscule vibration of the structure was recorded with the aid of a high-speed digital camera, and the …


Development Of A Mathematical Model For Galvanic Cells, Joshua C. Johnson Jan 2021

Development Of A Mathematical Model For Galvanic Cells, Joshua C. Johnson

Electronic Theses and Dissertations

It is possible to utilize principles of equilibrium thermodynamics to model the voltage a battery renders as it powers a load in time and discharges. Similarly, consideration of the internal chemistry inside a battery, or galvanic cell, enables modeling thereof. This paper builds upon these principles and presents a derivation of the Nernst equation that utilizes this result to model discharge curves in time for different types of batteries. The Nernst equation relates chemical activity of the reagents inside a battery to the open circuit voltage rendered by the system. By combining the Nernst equation with Faraday's laws of electrolysis, …


In-Situ Process Monitoring For Metal Additive Manufacturing (Am) Through Acoustic Technique, Md Shahjahan Hossain Jan 2021

In-Situ Process Monitoring For Metal Additive Manufacturing (Am) Through Acoustic Technique, Md Shahjahan Hossain

Electronic Theses and Dissertations

Additive Manufacturing (AM) is currently a widely used technology in different industries such as aerospace, medical, and consumer products. Previously it was mainly used for prototyping of the products, but now it is equally valuable for commercial product manufacturing. More profound understanding is still needed to track and identify defects during the AM process to ensure higher quality products with less material waste. Nondestructive testing becomes an essential form of testing for AM parts, where AE is one of the most used methods for in situ process monitoring. The Acoustic Emission (AE) approach has gained a reputation in nondestructive testing …