• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.649-655
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• 2004

The behavior of biological particles in DAF (dissolved air flotation) process was analyzed by employing PBT (Population balance theory). After decline growth phase of activated sludge, the value of the initial collision-attachment efficiency was increased over than 0.35 corresponding relatively high value in the whole life cycle of microorganism. For practical application of DAF as a solid separation process. It is desirable that microbial particles should be operated to perform high solid removal efficiency in biological wastewater treatment.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.2
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• pp.365-374
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• 2001

Its a tendency to strengthen related international was as the importance on marine oil pollution recently becomes the issue. According to the regulation of IMO, oil discharge from ships is allowed under 15PPM only and oil filtering equipment is essential. Oily water separator of laminated plate type which is one of gravity type separator can be use as assistant equipment for the oil filtering system to meet the present IMO standard, because it fits well to process large amount of rich oil with high specific gravity. The purpose of this paper is to investigate an efficiency of oil/water separation with the characteristics of laminated plate arrangement. The analyse of oil contents for oil-water mixture were carried out in order to find an efficiency of oil/water separation and an experimental study was simultaneously carried out to investigate internal flow characteristics of separator by visualization method and PIV(Particle Image Velocimetry) measurement at three spaces of plates for 5, 10 and 15 mm with variation of inlet flow rates of $0.25m^3$/h and $0.5m^3$/h. The experimental results showed that the space of the plates acts a significant role in the separating process.

• Journal of the Korean Chemical Society
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• v.35 no.3
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• pp.219-225
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• 1991

Capillary zone electrophoresis (CZE) which is highly efficient separation technique has been domestically established having optimum detection sensitivity. By applying 20∼35 kV of electric potential to the narrow (50 ${\mu}m$ i.d.) capillary tubing filled with running buffer, this technique can quickly (< 20 min) separate the small quantities of sample with high separation efficiency (number of theoretical plates : 200,000∼500,000). Factors affecting the separation efficiency and resolution in CZE were examined by analyzing adenine and catecholamine derivatives.

• Progress in Superconductivity and Cryogenics
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• v.25 no.3
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• pp.1-6
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• 2023

We have been developing a new magnetic filter so that small sized paramagnetic substances can be separated even in a low magnetic field (lower than 2T). The developed filter is a packed ferromagnetic filament with a triangular cross section. The filament has a diameter of 120 ㎛ and a length of 3 mm, and is mechanically packed with a volume ratio of 17.6%. Using this filter, a magnetic separation experiment of hematite was carried out using a superconducting magnet at the field of 2T. Similarly, magnetic separation was performed using a conventional magnetic filter. It became clear that the separation efficiency of newly developed filter is high as that of conventional mesh filter. The smaller sized hematite (<3 ㎛) could be separated though conventional mesh filter could not separate.

• Progress in Superconductivity and Cryogenics
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• v.25 no.3
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• pp.13-17
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• 2023

Magnetic separation technology for small paramagnetic particles has been desired for the volume reduction of contaminated soil from the Fukushima nuclear power plant accident and for the separation of scale and crud from nuclear power plants. However, the magnetic separation for paramagnetic particles requires a superconducting high gradient magnetic separation system applied, hence expanding the bore diameter of the magnets is necessary for mass processing and the initial and running costs would be enormous. The use of high magnetic fields makes safe onsite operation difficult, and there is an industrial need to increase the magnetic separation efficiency for paramagnetic particles in as low a magnetic field as possible. Therefore, we have been developing a magnetic separation system combined with a selection tube, which can separate small paramagnetic particles in a low magnetic field. In the previous technique we developed, a certain range of particle size was classified, and the classified particles were captured by magnetic separation. In this new approach, the fluid control method has been improved in order to the selectively classify particles of various diameters by using a multi-stage selection tube. The soil classification using a multi-stage selection tube was studied by calculation and experiment, and good results were obtained. In this paper, we report the effectiveness of the multi-stage selection tube was examined.

• Progress in Superconductivity and Cryogenics
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• v.20 no.2
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• pp.6-10
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• 2018

Removal of iron oxide scale from feed-water in thermal power plant can improve power generation efficiency. We have proposed a novel scale removal system utilizing High Gradient Magnetic Separation (HGMS). This system can be applied to high temperature and pressure area. We have conducted the lab-scale model experiments using ${\varphi}50mm$ filters and it demonstrated high removal efficiency in HGMS, but scale-up of the system is required toward practical use. In this study, we conducted a large scale mock-up HGMS experiment. We used the superconducting solenoidal magnet with ${\varphi}400mm$ bore and demonstrated that our HGMS system can achieve sufficient scale removal capacity that is required to introduce into both off-line and on-line system.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.72.1-72.1
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• 2013

Even though current microlensing follow-up observations focus on high-magnification events due to the high efficiency of planet detection, it is very difficult to do a confident detection of planets in high-magnification events with extremely weak central perturbations (i.e., the fractional deviation is ${\delta}{\leq}0.02$). For the confident detection of planets in the extremely weak central perturbation events, it is needed both the high cadence monitoring and the high photometric accuracy. A next-generation ground-based observation project, KMTNet (Korea Microlensing Telescope Network), satisfies both the conditions. Here we investigate how well planets in high-magnification events with extremely weak central perturbations are detected by KMTNet. First, we determine the probability of occurrence of events with ${\delta}{\leq}0.02$. From this, we find that for ${\leq}100M_E$ planets in the separation of $0.2AU{\leq}d{\leq}20AU$, events with ${\delta}{\leq}0.02$ occur with a frequency of more than 70%, in which d is the projected planet-star separation. Second, we estimate the efficiency of detecting planetary signals in the events with ${\delta}{\leq}0.02$ via KMTNet. We find that for main-sequence and subgiant source stars, ${\geq}1M_E$ planets can be detected more than 50% in a certain range that has the efficiency of ${\geq}10%$ and changes with the planet mass.

• Journal of Biosystems Engineering
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• v.5 no.1
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• pp.43-50
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• 1980

The milling plants in Korea have been generally used the paddy-separator that operated in accordance with the principle of sieving action. This type of paddy separator was considered as inefficient, especially in relation to the new high-yielding varieties which have different size characteristics within their varieties and also as compared to traditional varieties. With the installation of modern paddy separator it may be possible to increase the overall milling system efficiency and to reduce the grain loss. This study was intended to identify and define important parameters required for assessing the separation performance of a tray-type paddy separator and to determine the optimum conditions of the inclination of separator-table. The results of the study were summarized as follows : (1) Separation performance can be given by use of many parameters found from the measurement of separator outputs. such as upper-tail recovery $(\varepsilon)$, purity of upper-tail $(\gamma)$ , separation recovery of brown rice $(\alpha)$, separation recovery paddy $(\beta)$, and efficiency of separator $(\epsilon)$, Among these para-meters , $\varepsilon$, $\gamma$, $\alpha$ and $\beta$, were designated , respectively, their independent properties of the paddy separator. In addition, their modes of variation due to a varied inclination of the separation table did not indicated in the same direction . However, the efficiency of separator had an advantage to indicate the overall characteristics of the separator performance with a clear optimum inclination condition of the separator table. (2) The optimum feed rate and maximum efficiency of the separator did not occur at the identical inclination of the separator table. Thus, for its practical operation it is necessary to compromise between the qualitative and quantitative performances of the separator. (3) The optimum setting of the separator table tested in the study showed to occur at its inclination of approximately $26^\circ<$/TEX> for the front and $8^\circ<$/TEX> for lateral.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.539-545
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• 2014

Styrene-acrylamide co-polymer was immobilized on porous partially sub-$2{\mu}m$ silica monolith particles and inner surface of fused silica capillary ($50{\mu}m$ ID and 28 cm length) to result in ${\mu}LC$ and CEC stationary phases, respectively, for separation of anomeric D-glucose derivatives. Reversed addition-fragmentation transfer (RAFT) polymerization was incorporated to induce surface polymerization. Acrylamide was employed to incorporate amide-functionality in the stationary phase. The resultant ${\mu}LC$ and CEC stationary phases were able to separate isomers of D-glucose derivatives with high selectivity and efficiency. The mobile phase of 75/25 (v/v) acetonitrile (ACN)/water with 0.1% TFA, was used for HPLC with a packed column (1 mm ID, 300 mm length). The effects of pH and ACN composition on anomeric separation of D-glucose in CEC have been examined. A mobile phase of 85/15 (v/v) ACN/30 mM sodium acetate pH 6.7 was found the optimized mobile phase for CEC. The CEC stationary phase also gave good separation of other saccharides such as maltotriose and Dextran 1500 (MW~1500) with good separation efficiency (number of theoretical plates ~300,000/m).

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.2
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• pp.52-60
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• 2001

The need to control the oil content in oily bilge water discharges to meet the increasing stringent seawater pollution standards has led to the development of gravity type separators. Among the several gravitational methods, a plate type oily water separator can be used as an assistant equipment for the oil filtering system to meet the present IMO standard of 15 ppm, because it is believed to be an efficient method dealing with a large amount of rich oil with high specific gravity. The purpose of this paper is to examine the efficiency of oil/water separation with the characteristics of separating plate arrangement. An experimental study was carried out to analyse an efficient treatment oil-water mixture with variation of operating parameters, including flow rates, inlet oil concentrations and the height between the plates. The experimental results show that the height between the plates has a significant effect on the separation efficiency. The best efficiency was acquired when the ration of the height between the plates the plates to distance(H/Ci) was 2 with lower inlet oil concentration and lower flow rate.