Modelling of a N2-O2 flowing afterglow for plasma sterilization

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Carlos Daniel Diogo Matias Pintassilgo (Author) FEUP; J. Loureiro (Author) Other; V. Guerra (Author) Other

Journal

Title: Journal of Physics D: Applied Physics

Vol. 38 No. 3

Pages: 417-430

ISSN: 0022-3727

Publisher: Institute of Physics Publishing

Indexing

ISI Proceedings

Scientific classification

FOS: Natural sciences > Physical sciences

Other information

Abstract (EN): A kinetic model for a flowing microwave discharge in N-2-O-2 at omega/(2pi) = 2450 and 915 MHz, in the pressure range p = 1-10 Torr, is constructed with the purpose of studying the conditions that maximize the concentrations of NO(B (2)Sigma) molecules and O(P-3) atoms, which are known to play a central role in the sterilization processes. The former are responsible for the emission of UV photons associated with the NObeta bands. The NO(B) concentration is found to pass through a maximum, at approximately 1-3% of O-2 added to the mixture, which is in good agreement with the measured maximum of UV emission intensity, and with the shortest time required for the inactivation of spores. For such an O-2 percentage, the NO(B) also remains in the afterglow, with only a small reduction, up to a few similar to100 ms. Furthermore, the NO(B) concentration peaks with increasing pressure, with the corresponding maximum shifted to lower O-2 percentages, in agreement with the observations of UV intensity. The concentration of O(P-3) atoms is practically unchanged along the afterglow, at least up to times as high as 100 ms

Language: Portuguese

Type (Professor's evaluation): Scientific