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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Visualization
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The Korean Society of Visualization
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Volume & Issues
Volume 14, Issue 2 - Aug 2016
Volume 14, Issue 1 - Apr 2016
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Multiphase Flow & Flow Visualization Laboratory
Park, Hyeong-Min ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 9~14
The study on the effect of the solar radiation on thermal comfort and ventilation performance in room space
Yeon, Seong Hyeon ; Lee, Hyo Joon ; Rhee, Gwang Hoon ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 19~26
DOI : 10.5407/JKSV.2016.14.1.019
Modern people spend much time at indoor space. So, People want to make better indoor air condition. But the facade of building is made of glass to be seen urbanely, the effect of solar radiation makes indoor environment worse. This study designs an open space affected by solar radiation with 4-way cassette air-conditioner. Using numerical simulation, this paper investigates thermal comfort and ventilation performance with discharge angles
. To study thermal comfort, this paper studies distribution of velocity, temperature and effective draft temperature. Also, this paper introduces concept of air age to study ventilation performance. The flow influenced by solar radiation determines thermal comfort and ventilation performance in room space. This study shows that discharge angle of 45 degree has better thermal comfort and ventilation performance than that of 30 degree.
A Study on the Lubricating Air-layer Detection Techniques with Digital Image Analysis in Flat Plate Air Lubrication Test
Park, SeongHyeon ; Lee, Inwon ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 27~32
DOI : 10.5407/JKSV.2016.14.1.027
The reduction of
emissions has been a key target in the Marine Industry since the IMO's Marine Environment Protection Committee published its findings in 2009. The representative emission index is termed as the EEDI (Energy Efficiency Design Index) for the new ships. Among various flow control techniques ever proposed, the air lubrication method is the one of most promising one in terms of practical applicability. The present study examines the basic characteristics of the flat plate test with intention of applying the air lubrication technology to the reduction of the resistance of a ship. Image analysis technique is proposed as a tool to quantify the effectiveness of the air lubrication method.
Hemodynamical analysis by viscosity characteristics of artificial blood for μ-PIV experiment of Radio-cephalic arteriovenous fistula(RC-AVF)
Song, Ryungeun ; Lee, Jinkee ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 33~39
DOI : 10.5407/JKSV.2016.14.1.033
Radio-cephalic arteriovenous fistula(RC-AVF) is the most recommended operation of achieving access for hemodialysis. However, it has high rates of early failure depending on the many haemodynamic conditions. To increase RC-AVF patency rate, many researches were performed by in-vitro experiment via artificial vessel and blood analogue fluid, and there were conflicting opinions about whether the non-Newtonian properties of blood have an influence on the flow in large arteries. To investigate the influence of viscoelasticity of blood within the RC-AVF, we fabricated three dimensional artificial RC-AVF and two kinds of blood analogue fluid. The velocity field of two fluids within the vessel were measured by micro-particle velocimetry(m-PIV) and compared with each other. The velocity profiles of both fluids for systolic phase were matched well while those for diastolic phase did not correspond. Therefore, it is desired to use non-newtonian fluid for in-vitro experiment of RC-AVF.
Development and performance test of a micro bubble irrigation system for root canal cleaning of tooth
Sung, Gilhwan ; Sung, Jaeyong ; Lee, Myeong Ho ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 40~45
DOI : 10.5407/JKSV.2016.14.1.040
Elimination of the smear layer and bacteria in the root canal is the most important in the endodontic treatment, and various irrigation devices have been developed. Nevertheless, it is hard to eliminate the smear layer and bacteria completely. In this paper, a micro bubble irrigation system has been developed for the root canal cleaning of tooth. Micro bubbles are generated when pressurized fluids passing through a porous material inside a hand-piece nozzle, and the bubbly flows excited by ultrasonic vibration are observed using a high-speed camera and a microscope. The results show that the diameter and number of bubbles increases with the applied pressure, and there found an optimum excitation frequency in order to minimize the bubble size. From in-vitro tests, it is also verified that the developed bubble irrigation system has the ability of antibacterial and infection removal. Thus, this biocompatible system would be well suited for root canal cleaning.
Turbulence in temporally decelerating pipe flows
Jeong, Wongwan ; Lee, Jae Hwa ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 46~50
DOI : 10.5407/JKSV.2016.14.1.046
Direct numerical simulations (DNSs) of turbulent pipe flows with temporal deceleration were performed to examine response of the turbulent flows to the deceleration. The simulations were started with a fully-developed turbulent pipe flow at the Reynolds number,
, based on the pipe radius and the laminar centerline velocity, and three different constant temporal decelerations were applied to the initial flow with varying dU/dt = -0.001274, -0.00625 and -0.025. It was shown that the mean flows were greatly affected by temporal decelerations with downward shift of log law, and turbulent intensities were increased in particular in the outer layer, compared to steady flows at a similar Reynolds number. The analysis of Reynolds shear stress showed that second- and fourth-quadrant Reynolds shear stresses were increased with the decelerations, and the increase of the turbulence was attributed to enhancement of outer turbulent vortical structures by the temporal decelerations.
Visualization of oxygen distribution on leaf surfaces using VisiSens oxygen planar optode system
Hwang, BaeGeun ; Kim, HyeJeong ; Lee, SangJoon ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 51~56
DOI : 10.5407/JKSV.2016.14.1.051
Oxygen is a key factor in aerobic reactions and most biological activities. Visualization of oxygen distribution of a chemical process or biological system has been a very challenging object despite of its significance and potential impact. To monitor and visualize the spatial distribution of oxygen concentration, various techniques such as electro-chemical probe, polarographic electrode, LIF(laser-induced fluorescence) and so on have been introduced. Oxygen planar optode which utilizes the oxygen quenching of fluorescence light is one of the currently available methods for time-resolved visualization of oxygen distribution on a planar surface. In this study, we utilized VisiSens oxygen planar optode system to visualize the spatial distribution of oxygen concentration on leaves of Korean azalea. As a result, temporal variation of oxygen concentration distribution caused by respiratory activity of the leaf could be quantitatively monitored.
Acoustothermal Heating of Polydimethylsiloxane Microfluidic Systems and its Applications
Sung, Hyung Jin ; Ha, Byunghang ; Park, Jinsoo ; Destgeer, Ghulam ; Jung, Jin Ho ;
Journal of the Korean Society of Visualization, volume 14, issue 1, 2016, Pages 57~61
DOI : 10.5407/JKSV.2016.14.1.057
We report a finding of fast(exceeding 2,000 K/s) heating of polydimethylsiloxane(PDMS), one of the most commonly-used microchannel materials, under cyclic loadings at high(~MHz) frequencies. A microheater was created based on the finding. The heating mechanism utilized vibration damping of sound waves, which were generated and precisely manipulated using a conventional surface acoustic wave(SAW) microfluidic system, in PDMS. The penetration depths were measured to range from
, enough to cover most microchannel heights in microfluidic systems. The energy conversion efficiency was SAW frequency-dependent and measured to be the highest at around 30 MHz. Independent actuation of each interdigital transducer(IDT) enabled independent manipulation of SAWs, permitting spatiotemporal control of temperature on the microchip. All the advantages of this microheater facilitated a two-step continuous flow polymerase chain reaction(CFPCR) to achieve the billion-fold amplification of a 134 bp DNA amplicon in less than 3 min. In addition, a technique was developed for establishing dynamic free-form temperature gradients(TGs) in PDMS as well as in gases in contact with the PDMS.