• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.213-214
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• 2000

입자상 물질을 제거하기 위한 수단으로는 싸이클론, 필터, 전기집진기, 세정탑 등이 있다. 이중에 세정탑은 설치 및 운전이 편리한 반면, 미세 입자 제거 효율이 낮아 산업체에서 제한적으로 사용되고 있다. 이러한 결점, 즉 미세 입자의 제거 효율을 높이기 위해 다양한 형태의 세정탑이 연구되었으나(Laitinen et al., 1997; Fan et al., 1988), 대부분 실험적인 연구로서 세정탑에서 입자의 제거 기작이나 크기 분포 특성을 설명하지는 못한다. (중략)

• Analytical Science and Technology
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• v.22 no.1
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• pp.75-81
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• 2009

A flow and sedimentation field-flow fractionation method has been used to characterize colloidal particles in environmental samples. The opposed flow sample concentration (OFSC) method was employed. The OFSC procedure was optimized for the analysis of particles in ground water with respect to various experimental parameters including sample introduction time, flow rates, etc. The effectiveness in low concentration and characterization of the OFSC-FlFFF was demonstrated with GW-1 and GW-2 ground water samples. Ground water of upto 100 mL has been successfully loaded, concentrated, and characterized by OFSC-FlFFF. The OFSC technique allow the application of FlFFF possible for the separation and characterization of colloidal particles in very low concentrations. The results show FFF provides a simplified alternative to existing off-line concentration procedures, and shows a high potential for the applications to the analysis of dilute colloidal particles in the environmental samples.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.2
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• pp.84-95
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• 2014

Recently, as a variety of techniques of CMF (Compressed media filter) that has advantages of high porosity and compressibility have been developed in the U.S. and Japan. Therefore, the interest of intensive wastewater treatment using CMF has grown. This study examined the feasibility of CMF with varying sewage water quality to determine the optimum operating conditions. A preliminary tracer test that investigated the filtering process under various compression and flow rate conditions was performed. In a high compression condition, different porosities were applied to each depth of the column. Therefore, a distinct difference between a theoretical value and results of tracer test was observed. For the TSS (Total suspended solid) removal and particle size distribution of CMF for pre-treatment water under the various compression conditions, the compression ratio of 30 percent as the optimal condition showed greater than 70% removal efficiency. In addition, the compression ratio of >15% was required to remove small-sized particles. Also, an additional process such as coagulation is necessary to increase the removal efficiency for < $10{\mu}m$ particles, since these small particles significantly influence the effluent concentration. Modeling results showed that as the compression rate was increased, TSS removal efficiency in accordance with each particle size in the initial filtration was noticeably observed. The modeling results according to the depth of column targeting $10{\mu}m$ particles having the largest percentage in particle size distribution showed that 150-300 mm in filter media layer was the most active with respect to the filtering.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.609-615
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• 2005

$TiO_2$ particles, 30-300 nm in diameter, were prepared by thermal decomposition of titanium tetraisopropoxide (TTIP) using an aerosol microreactor, by which about $1{\mu}l$ of the liquid precursor is injected into an evaporator, 1 cc in volume, and vaporized precursor is then transported by nitrogen as a bolus to a tubular reactor 4 mm in diameter and 35 cm in length. Investigated were the effects of the reactor temperature and the concentration of TTIP vapor on the morphology, particle size distribution and crystalline structure of produced $TiO_2$ particles. With TTIP vapor concentration kept constant at 1 mol%, the reactor temperature was varied from 300 to 500 and $700^{\circ}C$. The primary particle size decreased with increasing the temperature, and the size distributions were mono-modal at 300 and $500^{\circ}C$, but bi-modal at $700^{\circ}C$. The TTIP vapor concentration was increased from 1 to 3.5 and 7 mol%, holding the reactor temperature at $700^{\circ}C$. The bi-modal distribution seen at the concentration of 1 mol% disappeared and the number of particles composing an agglomerate increased at the higher concentrations. These effects of the reactor temperature and the precursor concentration were discussed in comparison with experimental results reported earlier.

• Clean Technology
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• v.7 no.3
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• pp.169-178
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• 2001

Textile printing prints around twenty bilion linear meters of textile each year. Rotary and flat bed screen printing requires pre and post treatments, leading to the loss of dyes and the environmental problems due to effluents. Digital ink jet printing can offer a solution to the existing problems, especially the environmental problems, in addition to its flexibility. Pigments are used as a dispersion inks in the digital inkjet textile printing. Molecular dynamic simulation like Stokesian dynamic simulation was employed to simulate the behavior of pigments and velocity distribution under the pressure driven flow in the printer nozzle. The simulation shows that the particle distribution in the flow are uniform if particle volume fraction is low, the ratio of nozzle and particle diameter is large, and the dimensionless average suspension velocity is low.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.454-460
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• 2019

The purpose of this study is to analyze the distribution characteristics of mist spray particle size by devising a rotary mist spraying device to develop the evaporative salt water desalination system. The rotary mist spraying device was consisted of a BLDC sirocco fan, a spinning fan, a fan fixed shaft and a salt water supply device etc. In this study we analyzed the characteristics of spray particle size and distribution according to the variation of sirocco fan surface roughness(Ra, ${\mu}m$), revolutions(rpm) and salt water flow rate(mL/min). When sirocco fan surface roughness(Ra) was in the range of $0.27{\sim}7.65{\mu}m$, the spray particle size was $0.117{\sim}1.360{\mu}m$. And then more than 90% of spray particles were found to be less than $0.50{\mu}m$. When sirocco fan surface roughness(Ra) was in the range of $12.70{\sim}22.84{\mu}m$, the spray particle size was $2.51{\sim}184.79{\mu}m$ and more than 98% of spray particles were found to be less than $13.59{\mu}m$. To analyze the effect of fan rotation speed on the size and distribution of spray particles, when surface roughness Ra was fixed $0.27{\mu}m$ and fan rotation speed and salt water flow rate was respectively changed at 3,800~5,600 rpm and 2.77~8.28 mL/min, spray particle size was $0.314{\sim}0.541{\mu}m$. And when salt water flow rate was 9.74 mL/min and fan rotation speed was 3,800~5,200 rpm, spray particle size was in the range of $29.29{\sim}341.46{\mu}m$ and in case of 5,600 rpm more than 98.23% of spray particles were in the range of $2.51{\sim}13.59{\mu}m$.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.258-258
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• 2021

본 연구에서는 다양한 크기로 구성되어 있는 부유사의 연직방향 농도 분포와 흐름 특성을 동시에 모의할 수 있는 1차원 유사이동 모형을 제시하였다. 하상재료와 부유사의 입도분포를 고려하기 위해 유사입자의 크기범위를 여러 계급구간으로 분할하였으며, 각 계급구간에서 입경별 한계소류력은 Shields의 무차원 관계식을 바탕으로 산정하였다. 수치모형의 검증은 실험실 실험자료와의 비교를 통해 수행하였다. 수집한 실험실 실험자료에서는 연직방향으로의 유속분포와 농도의 분포, 부유사의 입도분포가 모두 제공된다. 수치모의 결과로부터 부유사 계산 과정에서 대표입경을 가정하여 적용하는 경우에 비해 여러 계급구간을 분할하는 경우 수치모의 결과의 정확도가 향상되는 것을 확인하였다. 이러한 모의 결과는 이전의 연구사례에서 확인된 바 있다. 또한 하상으로부터의 거리가 멀어질수록 부유사의 입도분포가 양으로 왜곡되는 현상 또한 계산결과에서 확인되었다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1989.11a
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• pp.19-19
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• 1989

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1997.10a
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• pp.135-136
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• 1997

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1998.10a
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• pp.152-153
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• 1998