• Journal of the Korean Society of Visualization
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• v.8 no.4
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• pp.48-53
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• 2010

Water-uptake through roots, is an essential process of the water flow in plants. Its visualization is very useful for understanding sap flow dynamics at whole plant level. In this study, the tips of Arabidopsis' root hairs were excised and exposed to repeated dehydration and rehydration processes. The water-refilling through individual xylem vessels was visualized using the synchrotron X-ray micro-imaging technique. The high temporal resolution ($2\;{\mu}m$) and beam intensity of the X-ray source allowed to acquisition of consecutive X-ray images of the water-refilling process up to 10 frames/sec. Various flow patterns were observed and the ascending speed of the water-air interfaces was analyzed. The relation between the water-rising height and ascending speed was also analyzed. The present results would provide better alternative for investigating sap flows in roots.

• Journal of the Korean Society of Visualization
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• v.22 no.2
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• pp.20-26
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• 2024

Water management is crucial for the performance, durability, and stability of Polymer Electrolyte Membrane Fuel Cells (PEMFCs). Due to its importance, various methods for visualizing PEMFC's internal water distribution have been adapted to study and manage water within the cells. However, these methods often require large facilities, leading to high costs and significant barriers to entry. This study addresses these challenges by using a commercial Radiation (X-ray) Generator (RG) for internal water distribution visualization and comparing the results with synchrotron X-ray data from the Pohang Accelerator Laboratory (PAL) 9D beamline. Despite the lower resolution and potential beam distortion challenges, the RG shows promise for PEMFC water distribution visualization, suggesting the need for further research to refine water attenuation coefficients and build-up factors for improved measurement accuracy.

• Journal of the Korean Society of Visualization
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• v.5 no.2
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• pp.33-38
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• 2007

Water management in polymer electrolyte fuel cell (PEFC) has been receiving large attention as an important issue in practical applications. Proper water management is vital to achieve high performance and durability of PEFC. In this study, an X-ray imaging technique was employed to visualize the water distribution in a PEFC quantitatively. X-ray images of the PEFC components with and without water were distinguished clearly. From the visualized X-ray images, we could evaluate the water distribution in the region between separator and gas diffusion layer (GDL) quantitatively. In addition, the contact angle of water in the micro-channels was also clearly visualized.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.155-158
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• 2007

Water management for Polymer Electrolyte Fuel Cell (PEFC) has been receiving large attention as an important issue in practical applications. Proper water management is vital to achieve high performance and durability of PEFC. In this study, an X-ray imaging technique was employed to visualize the water distribution in a PEFC quantitatively. X-ray images of the PEFC components with and without water are distinguished clearly. From the visualized X-ray images, we could confirm the water distribution in the region between separator and gas diffusion layer (GDL). In addition, the contact angle of water in the micro-channels was also clearly visualized..

• Journal of the Korean Society of Visualization
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• v.3 no.1
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• pp.20-25
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• 2005

An x-ray PIV (Particle Image Velocimetry) technique was developed fur measuring quantitative information on flows inside opaque conduits and/or opaque-fluid flows. To check the performance of the x-ray PIV technique developed, it was applied to a liquid flow in an opaque Teflon tube. To acquire x-ray images suitable for PIV velocity field measurements, the refraction-based edge enhancement mechanism was employed with seeding detectable tracer particles. The amassed velocity field data obtained were in a reasonable agreement with the theoretical prediction. The x-ray PIV technique was also applied to get velocity fields of blood flow and to measure size and velocity of micro-bubbles simultaneously, and to visualize the water refilling process in bamboo leaves. The x-ray PIV was found to be a powerful transmission-type flow imaging technique fur measuring quantitative information of flows inside opaque objects and various opaque-fluid flows.

• Journal of the Korean Society of Visualization
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• v.8 no.2
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• pp.45-50
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• 2010

The objective of this study is to elucidate the feasibility of synchrotron X-ray micro CT as a non-destructive imaging method to visualize the three-dimensional morphological structures of biological and non-biological samples. The experiments were conducted in 7B2 X-ray micro CT beamline in Pohang Accelerate Laboratory (PAL). A rotational 3-axis stage was specially designed for $0^{\circ}-180^{\circ}$ scanning of test samples. Preliminary tests were performed for opaque samples including a mosquito head, a plant seed and gas diffusion layer (GDL) of polymer electrolyte fuel cell to verify the feasibility of the X-ray micro CT. It visualized clearly the internal structure of all the test samples, supporting its usefulness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2083-2090
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• 2010

This paper presents a 3-D visualization technique using stereo radioactive images to provide efficient inspection of fast moving cargo objects. The proposed technique can be used for such objects which CT or MRI cannot inspect due to restricted scan environment. Stereo radioactive images are acquired from a specially designed equipment which consists of a X-ray source, linear radioactive sensors, and a moving stage. Two radioactive sensors are installed so that rectified stereo X-ray images of objects are acquired. Using the stereo X-ray images, we run a matching algorithm to find the correspondences between the images and reconstruct 3-D shapes of real objects. The objects are put in a parallelepiped box to simulate cargo inspection. Three real objects are tested and reconstructed. Due to the inherent ambiguity in the stereo X-ray images, we reconstruct 3-D shapes of the edges of the objects. The experimental results show the proposed technique can provide efficient visualization for cargo inspection.

• Journal of the Korean Society of Visualization
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• v.4 no.2
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• pp.69-75
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• 2006

The microbubbles were used in various fields, such as turbulent control, drag reduction, material science and life science. The X-ray PTV using X-ray micro-imaging technique was employed to mea-sure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Micro-bubbles of $10{\sim}60{\mu}m$ diameter moving upward in an opaque tube (${\phi}$=2.7mm) were tested. Due to the different refractive indices of water and air, phase contrast X-ray images clearly show the exact size and shape of over-lapped microbubbles. In all of the working fluids tested (deionized water, tap water, 0.01 and 0.10M NaCl solutions), the measured terminal velocity of the microbubbles rising through the solution was proportional to the square of the bubble diameter. The rising velocity was increased with increasing mole concentration. The microbubble can be useful as contrast agent or tracer in life science and biology. The X-ray PTV technique should be able to extract useful information on the behavior of various bio/microscale fluid flows that are not amenable to analysis using conventional methods.

• Journal of the Korean Society of Visualization
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• v.5 no.1
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• pp.30-36
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• 2007

The global environment is deteriorating at an alarming rate, despite of enhanced international environmental regulation. Many studies have been performed to reduce toxic pollutants. Recently, plant-based phytoremediation technology for moving toxic contaminants from soil and water has been receiving large attention. Arsenic-contaminated soil is one of the major pollutant sources for drinking water. Pteris erotica has been known as a hyper-accumulator of arsenic from soils. In this study, we investigated the effect of arsenic absorption on sap flow inside xylem vessels of Pteris. The synchrotron X-ray micro-imaging technique was employed to monitor the refilling process of water containing arsenic inside the xylem vessels of Pteris's leaves and stems non-invasively. The captured phase-contrast X-ray images show both anatomy of internal structure and transport of water inside Pteris. The exposure of Pteris to arsenic solution was found to increase largely the water raise speed in xylem vessels. The present results would provide important information needed for understanding the mechanisms of accumulation and transportation of toxic materials in plants.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.31-34
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• 2002

Imaging techniques using x-ray beam at high energies (>6KeV) such as contact radiography, projection microscopy, and tomography have been used to nondestructively discern internal structure of objects in material science, biology, and medicine. This paper introduces the x-ray micro-imaging method using 1B2 micro-probe line of PAL (Pohang Accelerator Laboratory). Cross-sectional information on low electron density materials can be obtained by probing a sample with coherent synchrotron x-ray beam in an in-line holography setup. Living organism such as plants, insects are practically transparent to high energy x-rays and create phase shift images of x-ray wave front. X-ray micro-images of micro-bubbles of $20\~120\;{\mu}m$ diameter in an opaque tube were recorded. Clear phase contrast images were obtained at Interfaces between bubbles and surrounding liquid due to different decrements of refractive index.