• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.100-102
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• 1999

We have analyzed AVHRR global data set for obtaining aerosol and cloud microphysical parameters, i. e., optical thickness and size index of particle polydispersions. From the results, it is found that the cloud optical thickness increases with increasing aerosol column number, which seems to be caused mainly by decreasing cloud particle radius, The cloud liquid water path was observed to be relatively constant without a significant dependence on the aerosol number. Further comparison of the satellite results with a general circulation model simulation.

• Journal of ILASS-Korea
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• v.19 no.3
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• pp.130-135
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• 2014

This study was performed to reveal the relationships between various gas supply conditions including inlet numbers and positions for Photobioreactor. To do that, this study was installed the experimental apparatus. All experiments were performed for the cases with 1, 2, 3, and 4 inlets and for gas flow rate of 4~8 lpm. Through the experiments, this study showed that the case with 3 or 4 inlets could reduce about 50% of the pressure loss head for all gas path than that of one inlet base case. So, these results can be used as basic data to design the gross or multiple photobioreactor.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.176-181
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• 2006

Experiments of Counter-Current Flow Limit(CCFL or Flooding) is performed to improve the drawbacks of Wallis' Correlation which neglects the effects of channel size, channel length, injection method and the boundary conditions at the inlet of liquid and gas phase. In this study, CCFL is observed by changing shape of porous plate using air and water. Results show that as the size of porous increases, CCFL with round shape of the porous plate decreases. In the present study, a CCFL correlation is developed and the CCFL map is proposed based on the present experimental results. developed by this experimental study.

• The Journal of Engineering Geology
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• v.14 no.2
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• pp.179-187
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• 2004

This study conducted a laboratory work to determine the change of dielectric constant of saturated soil porous media, which is injecting EML to use Frequency Domain Reflectometry(FDR) system and length 7cm-length measurement sensor. It is purpose of study that estimate a movement path through pore of soil for an ethanol mixing liquid(EML) which have the same specific gravity of water at $20{\;}^{\circ}C$, and determine to a dielectric measuring range for the measurement sensor. As an outflow point of saturated soil column upper part recedes from an EML inject point in EML diffusion test, the diffusion extent of EML through pore of saturated soil was expanded. And results of ail EML flow experiment were measured the change of dielectric constant at all measurement sensors which are placed to constant interval at the same travel time for saturated soil column. Therefore, the displace process of water that exist in pore of saturated soil by EML injection is enough available and confirm together mobility through pores.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.137-147
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• 2008

Soil Vapor Extraction (SVE) has been extensively used to remove volatile organic compounds (VOCs) from the vadoze zone. In order to investigate the removal mechanism during SVE operation, laboratory modeling experiments were carried out and tailing effect could be observed in later stage of the experiment. Tailing effect means that removal rate of contaminants gets significantly to decrease in later stage of SVE operation. Also, mathematical model simulating the tailing effect was used, which considers rate-limited diffusion in a water film during mass transfer among gas, liquid, and solid phases. Measurement data obtained through the experiment was used as input data of the numerical analyses. Sensitivity analysis was performed to examine the effect of each parameter on required time to reach final target concentration. Finally, it was found that the concentration in the soil phase decreased significantly with a liquid and gas diffusion coefficient larger, actual path length shorter, and water saturation smaller.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.473-481
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• 1997

Enhanced videomicroscopy was used to observe the dynamic behavior which occurred when water containing pure nonionic surfactant was carefully contacted with equal volumes of polar oils such as oleyl alcohol and oleic acid at various temperatures. A key component of the system is a vertical-stage microscope which provides for stable interfaces by locating the oil above the denser aqueous phase. This arrangement allowed intermediate phases formed at the surface of contact to be clearly observed, as well as any spontaneous emulsification which developed. Contacting experiments with $C_{12}E_5$ as the surfactant and with pure oleyl alcohol and oleic acid soils showed little activity below the cloud point but vigorous activity at higher temperatures including formation of an intermediate lamellar liquid crystalline phase. Diffusion path theory, which allows prediction of spontaneous emulsification resulting from diffusion and of intermediate phase formation during contacting processes, was used to understand the dynamic behavior seen during contacting experiments. Tentative diffusion paths for the contacting experiments with pure oleyl alcohol were presented with the aid of a partial phase diagram of the oleyl alcohol-water-$C_{12}E_5$ system.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.326-329
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• 2005

Proton exchange membrane (PEM) should be sufficiently hydrated with proper water management to maintain a good ionic conductivity and performance of a PEM fuel cell. However. cathode flooding resulting from excess water can impede the transport of reactants and hence deteriorate the fuel cell performance. For the PEM fuel cell to be commercially viable as vehicle or portable applications, the flooding on the cathode side should be minimized during the fuel cell operation. In this study, visualization technique was applied to understand the cathode flooding phenomena on the cathode side of a PEM fuel cell. To this end. a transparent PEM unit fuel cell wi th an act ive area of $25cm^2$ was designed and manufactured to allow for the visualization of cathode channel with performance characteristics. Two-phase flow resulting from the electro-chemical reaction of fuel cell was investigated experimentally. The images photographed by CCD camera with cell operating temperatures $(30\~50^{\circ}C)$ were presented. Results indicated that the flooding on the cathode side first occurs near the exit of cathode channel. As the operating temperature of fuel cell increases. it was found that liquid water droplets tend to evaporate easily and it can have an influence on lowering the flooding level. It is expected that this study can effectively contribute to the detailed researches on modeling water transport of an operating PEM fuel cell including two-phase flow phenomena.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.156-161
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• 2007

A set of experiments of counter-current flow limit (CCFL) was performed to improve the drawbacks of Wallis' correlation which neglected the effects of channel size, channel length, injection method and the boundary conditions at the inlet of liquid and gas phase. In this study, CCFL was observed by changing the shape of porous plate using air and water. The results show that as the size of porous increases, CCFL with a round shape of the porous plate start to disappear, In this study, the CCFL correlation was calculated and the corresponding CCFL map was developed based on the experimental results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.9
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• pp.477-483
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• 2013

A numerical analysis of solid-liquid phase change was performed on a heat transfer module which consisted of circulating water path (BRINE), heat transfer plate (HTP) and phase change material (PCM) layers, such as high temperature PCM (HPCM, $78{\sim}79^{\circ}C$) and low temperature PCM (LPCM, $28{\sim}29^{\circ}C$). There were five arrangements, consisting of BRINE, HTP, LPCM and HPCM layers in the heat transfer module. The time and heat transfer rate for melting/solidification was compared to their arrangements, against each other. As results, the numerical time without convection was longer than the experimental one for melting/solidification. Moreover, the melting/solidification with the BRINE I-LPCM-BRINE II-HPCM arrangement was faster(10 hours) than the others; HPCM-BRINE-LPCM, BRINE I-HPCM-LPCM-BRINE II one.

• Atmosphere
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• v.23 no.3
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• pp.321-329
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• 2013

This study examines the effect of aerosols on the vertical invigoration of continental stratiform clouds, using a dataset of Atmospheric Radiation Measurement (ARM) Intensive Operational Period (IOP, March 2000) at the Southern Great Plains (SGP) site. To provide further support to our observation-based findings, the weather research and forecasting (WRF) sensitivity simulations with changing cloud condensation nuclei (CCN) concentrations have been carried out for the golden episode over SGP. First, cross correlation between observed aerosol scattering coefficient and cloud liquid water path (LWP) with a 160-minutes lag is the highest of r = 0.83 for the selected episode, which may be attributable to cloud vertical invigoration induced by an increase in aerosol loading. Modeled cloud fractions in a control run are well matched with the observation in the perspective of cloud morphology and lasting period. It is also found through a simple sensitivity with a change in CCN that aerosol invigoration (AIV) effect on stratiform cloud organization is attributable to a change in the cloud microphysics as well as dynamics such as the corresponding modification of cloud number concentrations, drop size, and latent heating rate, etc. This study suggests a possible cloud vertical invigoration even in the continental stratiform clouds due to aerosol enhancement in spite of a limited analysis based on a few observed continental cloud cases.