Master of Science in Engineering, University of Akron, 2019, Electrical Engineering

This thesis proposes a technique for identifying deteriorated or contaminated electrical equipment. The technique uses the harmonic components of demodulated radio frequency (RF) and ultrasonic emissions to detect partial discharge (PD) events from faulty or contaminated components. The technique uses the sum-of-squares of the magnitudes of the first five 60-Hz harmonic components of the demodulated RF signal to detect the presence of faulty power system components. A parabolic acoustic noise detector captures ultrasonic emissions to pinpoint the physical location of the faulty power system component or components that causes the detected RF emissions. The proposed technique is capable of detecting all emissions detected, as well as others not detected, by the current industry standard – The Exacter Trigger. It is also more compact and portable, and it uses less data, requires fewer computations, and consumes less power. Single-chip digital signal processor implementations of the proposed technique are extensively validated via laboratory and field tests.

Committee: J. Alexis De Abreu Garcia (Advisor); Robert Veillette (Advisor); Michael French (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2011, Mechanical Engineering

An electrically excited oxygen-iodine laser with a scaled-up electric discharge has been designed and operated. Singlet delta oxygen is generated in a capacitively coupled RF discharge sustained in the plenum of a M=3 nozzle. The discharge operates at pressures up to p0=120 torr, powers up to 4.5 kW, and flow rates up to 0.5 mole/sec of 0-15 % O2 in He. Singlet delta oxygen yields up to Y=7.5 % have been measured using absolute infrared emission spectroscopy. Small signal gain on the I*(2P1/2,F′=3)→I(2P3/2,F″=4) iodine atom transition in the supersonic flow has been measured by tunable diode laser absorption spectroscopy, up to γ=0.209 %/cm. The addition of NO to the laser mixture and injection of chilled helium to reduce the laser mixture temperature have been shown to enhance laser performance considerably. Other modifications, including the addition of argon to the laser mixture, chilling the main flow through the electric discharge, and dissociating iodine directly by electron impact in an auxiliary electric discharge have not resulted in further gain increase. Laser action has been achieved using a transverse resonator in the supersonic cavity, with laser output power up to PL=7.8 W.

Committee: Igor Adamovich (Advisor); Walter Lempert (Committee Member); William Rich (Committee Member); Mohammad Samimy (Committee Member) Subjects: Mechanical Engineering