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United States Department of Agriculture

Agricultural Research Service

Title: Visualization of Aerocolloidal Biological Particles Using Two-Dimensional Particle Image Velocimetry (Piv)

Authors
item Hall, Carsie - UNO
item Masabattula, Sree - UNO
item Akyuzlu, Kazim - UNO
item Russo, Edwin - UNO
item Klich, Maren

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: September 1, 2003
Publication Date: December 1, 2003
Citation: Hall, C.A., Masabattula, S., Akyuzlu, K.M., Russo, E.P., Klich, M.A. 2003. Visualization of aerocolloidal biological particles using two-dimensional particle image velocimetry (piv). Proceedings of the Society of Photo-Optical Instrumentation Engineers. 5191:94-102.

Interpretive Summary: The mechanics of how fungal spores move about in the air is a relatively unexplored field. Understanding how spores are distributed is important to agriculture for determining how pathogenic and toxigenic fungi spread in the field as well as in storage. The need to understand pore movement has recently come to the forefront with the need to prevent bioterrorist attacks. In this study, methods were developed to track particles (including those of the toxigenic fungus Aspergillus versicolor) under controlled conditions.

Technical Abstract: Recent concerns over the possible use of airborne biological particles as weapons of mass destruction have significantly increased the attention that researchers are giving to this threat. The size of these particles, ranging from a fraction of a micrometer to several tens of micrometers, allows them to travel over long distances before settling out of the airstreams carrying these particles. Furthermore, the odd shapes of many of these particles, along with uncertainties about their light scattering characteristics, make detection and tracking quite a challenge. In the present paper, results are reported on the visualization of airborne biological particles using two-dimensional particle image velocimetry (PIV). These initial results show the utility of PIV in illuminating and tracking airborne biological particles. A compressed air nebulizer is used to aerosolize the biological particles inside a Plexiglas test section. The biological particles prepared for the nebulizer are first inoculated and cultured onto agar media, gypsum board, and acoustic ceiling tile to achieve an abundant growth of spores. A colloidal suspension of biological particles is then made using sterilized, de-ionized water and a mild surfactant to de-agglomerate the biological particles in the suspension. The concentration of biological particles in the colloidal suspension is determined using a hemacytometer. In the visualization experiments, images are captured for polystyrene latex (PSL) test particles, liquid water droplets, and spores of the fungal species Aspergillus versicolor. During the PIV system operation, two successive images are captured with a time delay of 50 us to develop flow field velocities of the PSL test particles, liquid water droplets, and the A. veriscolor spores.

Last Modified: 11/28/2014
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