Date of Award

8-2004

Degree Type

Thesis

Degree Name

Master of Science

Major

Electrical Engineering

Major Professor

Igor Alexeff

Committee Members

J. Douglas Birdwell, Gregory Peterson

Abstract

Steady-state atmospheric pressure nonthermal plasmas can splendidly debilitate bacteria in liquids, gases and on surfaces, as well as can disintegrate hazardous chemicals. The nonthermal gas discharge at atmospheric pressure, such as resistive barrier discharge is investigated for low temperature sterilization purposes. In specific, exploring and understanding the hidden secrets of the plasma sterilization mechanisms and the intensification of the main microbial reduction pathways are the objectives of the research.

A dual-mode steady-state atmospheric pressure resistive barrier ionized gas (plasma) generator has been designed and developed to meet the environmental health and federally mandated safety standards. Electrical, chemical, optical, and biological studies are carried out on the Steady-State, Atmospheric Pressure Resistive Barrier Discharge, with the intent of identifying the chemically and biologically active species produced. The goals of the research work are to prepare an effective, inexpensive plasma sterilization process and to identify and escalate the main contributing active species responsible for plasma sterilization.

The effectiveness of ionized gases produced by the resistive barrier plasma discharge on sterilizing bacteria has been analyzed. Bacteria at a dilution that achieved a countable number of colonies were exposed or not exposed to ionized gases for various periods of time and monitored to determine the effects of ionized gas treatment. The results of these experiments indicate that effective decontamination can be achieved within minutes when bacteria are exposed to ionized gases in close contact to the contaminating surface. On the battlefield or in remote locations, ionized gases could be used to decontaminate potentially harmful agents of bacterial origin. In hospitals on the battlefield and/or in remote locations, ionized gasses could be used to sterilize surgical equipment, decontaminate potentially infected areas in post-operative care units following surgery. In such cases the self-generated gas flow from the reactor facilitates the application of the ionized gases over the large infected areas.

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