Image processing methods to obtain symmetrical distribution from projection image.
Flow visualization and measurement of cross-sectional liquid distribution is very effective to clarify the effects of obstacles in a conduit on heat transfer and flow characteristics of gas-liquid two-phase flow. In this study, two methods to obtain cross-sectional distribution of void fraction are applied to vertical upward air-water two-phase flow. These methods need projection image only from one direction. Radial distributions of void fraction in a circular tube and a circular-tube annuli with a spacer were calculated by Abel transform based on the assumption of axial symmetry. On the other hand, cross-sectional distributions of void fraction in a circular tube with a wire coil whose conduit configuration rotates about the tube central axis periodically were measured by CT method based on the assumption that the relative distributions of liquid phase against the wire were kept along the flow direction.
Visualization and Measurement of Hygroscopic Water Distribution in a Unit Cell of Silica-Gel Adsorber by Neutron Radiography
Evaluation of hygroscopic water distribution in adsorber is important to design adsorption refrigerating system, because the adsorption and desorption process strongly affect on the cycle performance. A neutron radiography method was applied to a diagnosis of a silica-gel adsorber, such as nondestructive testing of the structure of particle layer and real-time measurement of hygroscopic water distributions. Silica gel particles of diameter around 0.5 mm were used. The attenuation coefficient of neutron beam for the silica gel particle layer was measured using a sample rectangular capsule. Then, a silica-gel unit was made by filling the silica-gel particles between fins on the outside of an aluminum cylinder. The particles were fixed with vinyl acetate glue. The internal structure of the unit was successfully visualized with the spatial resolution of 107 μm. From the visualized images, 3-D structure of the unit was clearly obtained by a computed tomography method. From the comparison between dry and wet condition, hygroscopic water distribution could be measured. Moreover, radial distribution could be obtained by Abel transform assuming the axial symmetry.
“Social Media Misinformation”—An Epidemic within the COVID-19 Pandemic
"Social Media Misinformation"-An Epidemic within the COVID-19 Pandemic.