Date of Award

Fall 2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Electrical & Computer Engineering

Program/Concentration

Electrical and Computer Engineering

Committee Director

Juergen Kolb

Committee Member

Christian Zemlin

Committee Member

Ravindra Joshi

Call Number for Print

Special Collections LD4331.E55 J323 2012

Abstract

The inactivation abilities of a nonthermal plasma jet were investigated with the yeast C. kefyr, a pathogen with increasing importance in healthcare. The plasma is generated using a microhollow cathode discharge (MHCD) geometry operated with a DC voltage of 2 kV and a current of 30 mA using air as the operating gas at an airflow rate of 8 SLM. The plasma discharge approaches room temperature at a few mm away from the plasma jet allowing for the use on heat sensitive surfaces. Dry air and humid air were used as the operating gas to see if humidity plays a significant role in the inactivation of C. kefyr. Different exposure times and different axial distances between the plasma jet and the C. kefyr inoculated petri dishes were tested. The yeast was completely inactivated in the treatment square for an exposure time of 215 s for both dry air and humid air exposures. Comparisons of the inactivation of C. kefyr using other plasma systems are discussed. Air ions, UV, and temperature were quantified and investigated as potential inactivation mechanisms. UV and temperature were shown not to be large mechanisms for the inactivation of C. kefyr. The air ion density measured near the plume and up to a meter away from the plume was greater than densities commonly observed during thunderstorms. Penetration depth of blood agar was investigated to determine how far past the surface the plasma interacts. For all axial distances measured from 10 to 40 mm between the plasma jet and the blood agar surface the afterglow interacted with the agar past the surface.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

DOI

10.25777/7b7a-dh20

Download

Share

COinS