title: Calibrating the X-ray attenuation of liquid water and correcting sample movement artefacts during in operando synchrotron X-ray radiographic imaging of polymer electrolyte membrane fuel cells.
abstract: Synchrotron X-ray radiography, due to its high temporal and spatial resolutions, provides a valuable means for understanding the in operando water transport behaviour in polymer electrolyte membrane fuel cells. The purpose of this study is to address the specific artefact of imaging sample movement, which poses a significant challenge to synchrotron-based imaging for fuel cell diagnostics. Specifically, the impact of the micrometer-scale movement of the sample was determined, and a correction methodology was developed. At a photon energy level of 20 keV, a maximum movement of 7.5 µm resulted in a false water thickness of 0.93 cm (9% higher than the maximum amount of water that the experimental apparatus could physically contain). This artefact was corrected by image translations based on the relationship between the false water thickness value and the distance moved by the sample. The implementation of this correction method led to a significant reduction in false water thickness (to ∼0.04 cm). Furthermore, to account for inaccuracies in pixel intensities due to the scattering effect and higher harmonics, a calibration technique was introduced for the liquid water X-ray attenuation coefficient, which was found to be 0.657 ± 0.023 cm(-1) at 20 keV. The work presented in this paper provides valuable tools for artefact compensation and accuracy improvements for dynamic synchrotron X-ray imaging of fuel cells.
authors.affiliation: Thermofluids for Energy and Advanced Materials Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8.
authors.forename: Nan
authors.initials: N
authors.lastname: Ge
authors.affiliation: Thermofluids for Energy and Advanced Materials Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Chevalier
authors.affiliation: Thermofluids for Energy and Advanced Materials Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8.
authors.forename: James
authors.initials: J
authors.lastname: Hinebaugh
authors.affiliation: Thermofluids for Energy and Advanced Materials Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8.
authors.forename: Ronnie
authors.initials: R
authors.lastname: Yip
authors.affiliation: Thermofluids for Energy and Advanced Materials Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8.
authors.forename: Jongmin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Thermofluids for Energy and Advanced Materials Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8.
authors.forename: Patrick
authors.initials: P
authors.lastname: Antonacci
authors.affiliation: EV System Laboratory, Research Division 2, Nissan Research Center, Nissan Motor Co. Ltd, 1 Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kotaka
authors.affiliation: EV System Laboratory, Research Division 2, Nissan Research Center, Nissan Motor Co. Ltd, 1 Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Tabuchi
authors.affiliation: Thermofluids for Energy and Advanced Materials Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8.
authors.forename: Aimy
authors.initials: A
authors.lastname: Bazylak
keywords: Beer–Lambert law; polymer electrolyte membrane fuel cells; sample movement; synchrotron radiography; water attenuation coefficient calibration