title: Concentration measurements of bubbles in a water column using an optical tomography system.
abstract: Optical tomography provides a means for the determination of the spatial distribution of materials with different optical density in a volume by non-intrusive means. This paper presents results of concentration measurements of gas bubbles in a water column using an optical tomography system. A hydraulic flow rig is used to generate vertical air-water two-phase flows with controllable bubble flow rate. Two approaches are investigated. The first aims to obtain an average gas concentration at the measurement section, the second aims to obtain a gas distribution profile by using tomographic imaging. A hybrid back-projection algorithm is used to calculate concentration profiles from measured sensor values to provide a tomographic image of the measurement cross-section. The algorithm combines the characteristic of an optical sensor as a hard field sensor and the linear back projection algorithm.
authors.affiliation: Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia. salleh@fke.utm.my
authors.forename: S
authors.initials: S
authors.lastname: Ibrahim
authors.forename: Mohd Amri Md
authors.initials: MA
authors.lastname: Yunus
authors.forename: R G
authors.initials: RG
authors.lastname: Green
authors.forename: K
authors.initials: K
authors.lastname: Dutton
mesh_terms: D000465:Algorithms; D003720:Densitometry / Q000379:methods*; D005740:Gases / Q000032:analysis*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D041622:Tomography, Optical / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D005740:Gases; D014867:Water