Characteristics of non-thermal atmospheric-pressure plasma generated in a coaxial cylindrical Dielectric-Barrier Discharge (DBD) were investigated for application in treatment of polymer and 100% un-mercerized cotton yarns. The discharge characteristics were investigated by measuring the electrical parameters and utilization of developed plasma circuit models to obtain plasma electron temperature, number density and the electron-neutral collision frequency. The experiments were conducted in helium and oxygenated helium plasma in absence and presence of yarns. The discharge is capacitively-coupled and is induced by an audio-frequency, 4.5 kHz, oscillating voltage. The electrical voltage-current (V-I) characteristics optimized for plasma processing, by the oxygen and helium flow rate ratio, was found to be about 40sccm for oxygen flow. Optical emission spectroscopy (OES) was used to determine the plasma composition and to evaluate plasma temperature and number density. The plasma electron number density decreased from 2.2 x 10^16 to 1.4 x 10^16 per cubic meter when oxygen flow rate was increased to 100sccm in a 10,000sccm helium flow, while the electron temperature increased from 0.15 to 0.4 eV for the same increase in oxygen flow rate. It was also found that the plasma experiences some streamers and that the streamer?s electron temperature has a wide range between 0.5 to 2 eV. The optimized oxygen flow rate for polymer yarn processing was found to be 40sccm in a 10,000sccm helium flow.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-12242007-142129 |
| Date | 08 January 2008 |
| Creators | Lee, Kyoung Ook |
| Contributors | Keith Weninger, Orlando E. Hankins, Mohamed A. Bourham |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-12242007-142129/ |
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