• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제42권2호
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• pp.86-96
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• 2006

This research aims at establishing the fundamental characteristics of the kite through the analysis of the flow field around various types of kites. The approach of this study were adopted for the analysis; visualization by PIV(particle image velocimetry). Also, the lift and drag tests of kites had been performed in our previous finding(Bae et al., 2004a; Bae et al., 2004b). For this situation, models of canvas kite were deployed in the circulating water channel for the PIV test using the same conditions as in the lift and drag tests. The results obtained from the above approach are summarized as follows: Given the rectangular and triangular kites when attack angle is $20^{\circ}$, vortex by the boundary layer separation was seen in the leading edge and the flow towards the trailing edge was more turbulent. But, the inverted triangular type kite was seen to be stable without any boundary layer separation or turbulence. The increase of the attack angle resulted in the eddy in order of the rectangular, triangular and inverted triangular type. The magnitude of the eddy followed the same order. The effect of edge-eddy was biggest in the triangular type followed by the rectangular and then the inverted triangular type. The kite as the buoyancy device or the opening device will be very useful when the appropriate applications and the stability are met.

• Analytical Science and Technology
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• 제24권4호
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• pp.249-255
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• 2011

Swelling of starch granules by water-sorption causes a progressive or sometimes abrupt change in sorption behavior as a result of structural alterations and the possible exposure of new sites with high affinity for water. It is thus of interest to examine the time-dependent change in the size or shape of the starch granules. Gravitational field-flow fractionation (GrFFF) utilizes the earth's gravity as the external field, and is useful for separation of micron-sized particles with larger particles eluting earlier than smaller ones. In this study, GrFFF was used to monitor the swelling of two starch granules, potato starch and sweet potato starch during contact time of 11-12 days at room temperature in water. Results from GrFFF were compared with those obtained from optical microscope (OM). For both starch granules, the mean sizes were increased with time spent in water.

• Journal of the Korean Applied Science and Technology
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• 제29권3호
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• pp.370-376
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• 2012

We fabricated linear low density polyethylene (LLDPE) particles via crystallization from decalin solution. In the thermally induced phase separation (TIPS) process, formation of particles occurred during controlled cooling of LLDPE/decalin solution. Despite an increase of nucleation and growth rate for crystals at higher polymer concentrations, which generally results in larger particles than at lower concentration, the average diameter of LLDPE particles increased as LLDPE was more concentrated in decalin solution. In the FE-SEM micrographs, the observed particles from various concentrations were smaller than 10 ${\mu}m$, showing spherical morphologies. In addition to its effect on size, concentration of LLDPE had an broadening effect on the particle size distribution.

• Proceedings of KOSOMES biannual meeting
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• 해양환경안전학회 2006년도 추계학술발표회
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• pp.53-58
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• 2006

Along with the development of costal engineering, various type of breakwaters have been built. The main purpose of breakwaters are to provide harbour protection against waves, to stabilize beaches against erosion due to large wave action, and to provide for temporary wave protection for installation on or under water surface. This paper an application example of PIV system for analyzing the flow of Floating Breakwater with double barriers. We introduce an analysis method to predict the characteristics of flow around the neighboring fields of Floating Breakwater with double barriers in order to develop a high performance model. Flow visualization has conducted in circulating water channel by a high speed camera and etc. Flowing phenomenon according to velocity distribution and flow separation around the breakwater with double barriers were obtained by 2-D PIV system.

• Journal of Korean Society of Water and Wastewater
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• 제32권5호
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• pp.399-409
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• 2018

Prussian blue is known as a superior material for selective adsorption of radioactive cesium ions; however, the separation of Prussian blue from aqueous suspension, due to particle size of around several tens of nanometers, is a hurdle that must be overcome. Therefore, this study aims to develop granule type adsorbent material containing Prussian blue in order to selectively adsorb and remove radioactive cesium in water. The surface of granular activated carbon was grafted using a covalent organic polymer (COP-19) in order to enhance Prussian blue immobilization. To maximize the degree of immobilization and minimize subsequent detachment of Prussian blue, several immobilization pathways were evaluated. As a result, the highest cesium adsorption performance was achieved when Prussian blue was synthesized in-situ without solid-liquid separation step during synthesis. The sample obtained under optimal conditions was further analyzed by scanning electron microscope-energy dispersive spectrometry, and it was confirmed that Prussian blue, which is about 9.7% of the total weight, was fixed on the surface of the activated carbon; this level of fixing represented a two-fold improvement compared to before COP-19 modification. In addition, an elution test was carried out to evaluate the stability of Prussian blue. Leaching of Prussian blue and cesium decreased by 1/2 and 1/3, respectively, compared to those levels before modification, showing increased stability due to COP-19 grafting. The Prussian blue based adsorbent material developed in this study is expected to be useful as a decontamination material to mitigate the release of radioactive materials.

• Resources Recycling
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• 제23권5호
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• pp.36-43
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• 2014

It comtained various kinds of heavy metal in beneficiatian tailing and in order to eliminate the heavy metals, various technologies have been researched, But there are a limits because many problems and restrictions are accompanied. Therefore, in this study, in order to solve this problem, It was performed gravity separation using melti-gravity seperator (MGS) to remove As contained in tailing, which can sort out even the fine particle. It was attempted a study to remove As, which is a kind of heavy metals, by MGS gravity separation and verified the impact by slope, wash water, pulp density, rotational speed and feed rate. In the results of performing gravity concentration under the condition with the MGS slope of $3^{\circ}$, wash water of 5 l/mm, pulp density of 30%, rotational speed of 208 rpm, and the feed rate of 265.24 g/mm, the As removal rate of 88.21% and yield of 92.25% were obtained.

• Mass Spectrometry Letters
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• 제5권1호
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• pp.24-29
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• 2014

An advanced and reliable high performance liquid chromatography (HPLC)/ultraviolet detector (UV)/ion-trap time-of-flight (IT-TOF) mass spectrometry was developed for the simultaneous quantification of 19 marker compounds in Bang-poong-tong-sung-san (BPTS), a traditional oriental prescription. Various parameters affecting HPLC separation and IT-TOF detection were investigated, and optimized conditions were identified. The separation was achieved on a Capcell PAK C18 column ($1.5mm{\times}250mm$, $5{\mu}m$ particle size) using a gradient elution of acetonitrile and water containing 0.1% formic acid at a flow rate of 0.1 mL/min. The column temperature was maintained at $40^{\circ}C$ and the injection volume was $2{\mu}L$. IT-TOF system was equipped with an electrospray ion source (ESI) operating in positive or negative ion mode. The optimized electrospray ionization parameters were as follows: ion spray voltage, +4.5 kV (positive ion mode), or -3.5 kV (negative ion mode); drying gas ($N_2$), 1.5 L/min; heat block temperature, $200^{\circ}C$. Automatic $MS^n$ (n = 1~3) analyses were carried out to obtain structural information of analytes. Elemental compositions and their mass errors were calculated based on their accurate masses obtained from a formula predictor software. The marker compounds in BPTS were identified by comparisons between $MS^n$ spectra from standards and those from extracts. Moreover, the libraries of $MS^2$ and $MS^3$ spectra and accurate masses of parent and fragment ions for marker compounds were constructed. The developed method was successfully applied to the BPTS extracts and identified 17 out of 19 marker compounds in the BPTS extracts.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3665-3670
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• 2012

Metal-p-$NH_2$-Bn-DOTA (paraammionobenzyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid: ABDOTA) complex was synthesized and purified for bio-tagging to quantify biological target materials using laser ablation (LA)-ICP-MS. Since the preparation of a pure and stable tagging complex is the key procedure for quantification, magnetic particles were used to purify the synthesized metal-ABDOTA complex. The magnetic particles immobilized with the complex attracted to a permanent magnet, resulting in fast separation from free un-reacted metal ions in solution. Gd ions formed the metal-complex with a higher yield of 64.3% (${\pm}3.9%$ relative standard deviation (RSD)) than Y ions, 52.3% (${\pm}2.5%$ RSD), in the pH range 4-7. The complex bound to the magnetic particles was released by treatment with a strong base, of which the recovery was 81.7%. As a reference, a solid phase extraction (SPE) column packed with Chelex-100 resin was employed for separation under similar conditions and produced comparable results. The tagging technique complemented polydimethylsiloxane (PDMS) microarray chip sampling in LA-ICP-MS, allowing determination of small sample volumes at high throughputs. For application, immunoglobulin G (IgG) was immobilized on the pillars of PDMS microarray chips and then tagged with the prepared Gd complex. IgG could then be determined through measurement of Gd by LA-ICP-MS. A detection limit of 1.61 ng/mL (${\pm}0.75%$ RSD) for Gd was obtained.

• Membrane Journal
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• 제15권4호
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• pp.349-354
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• 2005

YSZ (yttria-stabilized zirconia) determined with an electrolyte that analyzed thermal stability along sintering condition and an electric characteristic. As sintering temperature increases by SEM, grain grows and it showed that pore decreases relatively. and confirmed effect by grain size. It evaluated that particle internal resistance and electric performance by resistance in an electrolyte and electricity conductivity measurement through ac impedance measurement in temperature of $800\~1000^{\circ}C$ in 2-probe method In order to recognize an electric characteristic. In dry process and wet process, density was each 6.13, 6.25 $g/cm^3$ and the relative density was each 98, 99$\%$ when sintering condition is $1400^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• 제29권4호
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• pp.107-114
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• 2021

This study applied with pre-treatment combined with thermal hydrolysis and seperation for disintegration of sludge. As results of particle size distribution D10, D50 and D90 of thermal hydrolyzed and centrifuged sludge was 8.6, 59.2 and 425.1 ㎛, which are lower than those of thermal hydrolyzed. The molecular weight distribution results showed that the thermal hydrolyzed sludge showed the highest proportion in the 10-100kDa range. But, Sludge, treated with combined pre-treatment, showed the highest proportion <1kDa range. Results of DOC and UVA₂₅₄ found that the organic matters of hydrolyzed sludge composed high molecular weight component above 10kDa. While, the organic matters of sludge, treated by combined pre-treatment, composed relarively low molecular weight below 1kDa. The specific methane yield of hydrolyzed and centrifuged sludge was higher 1.7 times than that of only hydrolyzed sludge.