• Title/Summary/Keyword: 입자분리

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Self-propelled particle의 상 분리와 그에 대한 leader 및 seed입자의 영향

  • Jo, Yeong-Su;No, Chan-U;Jeong, Yeon-Jun
    • Proceeding of EDISON Challenge
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    • 2015.03a
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    • pp.76-82
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    • 2015
  • Active matter는 스스로 에너지를 가지고 움직이는 개체들이 서로 상호작용을 하여 집단적인 움직임을 보이는 물질이다. Rotational noise model은 반발 상호작용과 rotational noise를 가지고 있는 self-propelled particle로 active matter를 설명한다. 이 연구에서는 rotational noise model에서의 상 도표와 클러스터 형성을 알아보고 입자들의 집단적인 운동을 도와주거나 방해할 수 있는 leader 입자와 seed가 클러스터의 운동에 어떠한 영향을 주는지 알아본다.

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Electron Microscopical Property of Transglutaminase Added Milk (트랜스글루타미나제를 첨가한 우유의 전자현미경적 특성)

  • 문정한;홍윤호
    • Food Science of Animal Resources
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    • v.23 no.4
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    • pp.350-355
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    • 2003
  • Raw skim milk and colloidal calcium phosphate-free skim milk were treated with microbial transglutaminase (TGase), ultracentrifuged at varying rates and were observed to contain textural properties using a scanning electron microscope (SEM). Skim milk showed irregular signs of conformation at lower centrifugal rate, and associated regular (10,000 ${\times}$g) and thin with broad holes (20,000 ${\times}$g). The associated texture became thick and irregular (40,000 ${\times}$g), and fine particles were regularly associated (100,000 ${\times}$g). When skim milk was incubated for 1 hr with TGase, casein micelles aggregated and broadened as centrifugation rate increased. When skim milk was incubated for 8 hrs with TGase, casein micelles associated to large widened aggregates, and were associated regularly which then became irregular (100,000 ${\times}$g). When colloidal calcium phosphate-free skim milk incubated for 1 hr with TGase showed no sediment, the milk incubated for 8 hrs with TGase associated together, yielding broadened and regular layers as the centrifugation rate increased. It is assumed that such phenomena could be caused by protein crosslinking reaction with TGase and conformational change of casein molecules, as well as dependencies on reaction time, temperature and ultracentrifugation rate.

Mitigations of Natural Organic Matter Fouling of Polyethersulfone Microfiltration Membrane Enhanced by Deposition of $TiO_2$ Nanoparticles ($TiO_2$ 나노입자로 표면침적된 Polyethersulfone 정밀여과 분리막의 자연유기물 파울링 감소)

  • Chang, Jung-Woo;Ahn, Kyung-Min;Kim, Ki-Hyun;Khan, Sovann;Kim, Jeong-Hwan
    • Membrane Journal
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    • v.20 no.2
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    • pp.120-126
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    • 2010
  • In this study, the effect of surface deposition of $TiO_2$ nanoparticles at polyethersulfone (PES) microfiltraiton (MF) membrane on humic acid fouling was investigated. The effect was observed as a function of crystal structures of $TiO_2$ nanoparticles and solution chemistries including pH and divalent cation such as calcium. Our results showed clearly that $TiO_2$-deposited membrane could mitigate membrane fouling significantly. However, this effect was observed to be dependent upon crystal structures of $TiO_2$ nanoparticles and solution chemistries. In the absence of calcium, fouling mitigation was less pronounced for both anatase and hybrid $TiO_2$-deposited membrane than for rutile $TiO_2$-deposited membrane while opposite trend was observed after addition of calcium. In the presence of calcium, the adsorption of humic acid to $TiO_2$-deposited membrane can be reduced by electrostatic repulsions between humic acid and $TiO_2$ surface. Addition of calcium provided further beneficial effect on fouling mitigation particularly at higher pH for the anatase $TiO_2$ deposited membrane, implying that both increased hydrophilicity due to $TiO_2$ nanoparticles and negative surface charge of the membrane should affect fouling mitigation. However, rutile $TiO_2$ having more inertness generally than the anatase $TiO_2$ showed relatively robust effect on the fouling mitigation regardless of solution properties.

The Grinding Characteristics of the Metal Components in Printed Circuit Boards(PCBs) Scrap by the Swing-Hammer Type Impact Mill (충격형 분쇄기 에 의한 폐프린트배선기판(PCBs) 중 금속성분의 분쇄 특성)

  • 이재천;길대섭;남철우;최철준
    • Resources Recycling
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    • v.11 no.2
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    • pp.28-35
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    • 2002
  • A study on the grinding characteristics of metal components in printed circuit boards (PCBs) scrap by a swing-hammer typeimpact mill was conducted. The PCBs scrap crushed to sizes less than 3 mm were pulverized to liberate metal components by the impact mill. The effect of rotation speed of hammer on the grinding characteristics was investigated. The particle size distribution and degree of liberation of metals such as copper and solder were measured. The effect of rotation speed and particle size on the shape sorting of metal Particles from milled PCBs was investigated using an inclined vibrating Plate. At the hammer speed of 61.3 m/s about 80% of the copper particles became larger than 297 $\mu$m while 90% of solder particles was smaller than 297 $\mu$m. In the shape sorting method, the recovery location becomes shorter as the rotation speed of hammer increases. The recovery location for particles larger than 297$\mu$m was shorter than for particles sized between 149$\mu$m and 297$\mu$m. As the recovery location becomes shorter, KI value increases towards unity while $\phi_{c}$ value decreases towards unity indicating the more roundness of metal particles.

Analysis of a Continuous and Instantaneous Vacuum Drying System for Drying and Separation of Suspended Paricles in Waste Solvent (폐용제에 함유된 입자의 건조 및 분리용 연속식 순간 진공건조시스템 해석)

  • 구재현;이재근
    • Resources Recycling
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    • v.9 no.4
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    • pp.28-36
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    • 2000
  • This study describes to analyze the characteristics for separation and recovery of both the dried particles and the purified solvent from the waste solvent through the vaporization process by the continuous and instantaneous vacuum drying system. The vacuum drying system for the waste solvents recovery consists of a feeding pump, a double pipe heat exchanger, a vacuum spray chamber, and a condenser. The vacuum drying system heats the waste solvent to the vapor in the double pipe heat exchanger and the expanded vapor is sprayed at the end of the tube. The vaporized solvent in the condenser are recovered. The particles in the waste solvent are separated and dried from the vapor in the vacuum spray chamber. Performance evaluation of the vacuum drying system was conducted using the mixture of the dried pigment particles and benzene or alkylbenzene as test samples. For the mixture of 10 wt% pigment particles an 90% benzene, the recovery efficiency of benzene was 88% with the purity of 99% and the recovery efficiency of dried particles was 94% with the moisture of 1.1 wt%. The size of pigment particles was decreased from $6.5\mu\textrm{m}$ to $5.6\mu\textrm{m}$ in diameter due to high speed spraying and dispersion in the vacuum drying system during drying process. Therefore, the vacuum drying system showed to be an effective method for separating particles and solvent in the waste solvent.

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Gas Permeation Properties of CO2 and CH4 for PEBAX®/Fumed Silica Hybrid Membranes (PEBAX®/fumed silica 하이브리드 분리막을 통한 CO2와 CH4의 기체투과특성)

  • Kim, Hyunjoon
    • Membrane Journal
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    • v.32 no.1
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    • pp.74-82
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    • 2022
  • The objective of this work was to investigate the gas permeation properties of CO2 and CH4 for PEBAX®/TS-530 hybrid membranes and compare with pure PEBAX®-1657 membrane. With FTIR and XRD it was possible to confirm that TS-530 was dispersed well in PEBAX® matrix. Compared with pure PEBAX® membrane, ideal separation factor for PEBAX®/TS-530 (10 wt%) hybrid membrane was enhanced a little. As the amount of TS-530 was increased, the gas permeability coefficients of both CO2 and CH4 were increased, while the ideal separation factor was decreased. This results were explained by the reduction of crystallinity of polyamide block and interchain distance caused by introduction of inorganic nanoparticles. And fumed silica might tend to agglomerate, resulting in forming nonselective nanogaps in the hybrid materials, thus the diffusivity would be enhanced at the expense of diffusivity selectivity.

Performance Evaluation of a Electro-Double Cyclone (전기 Double Cyclone의 성능평가)

  • 임경수;김현수;이규원
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2003.05b
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    • pp.399-400
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    • 2003
  • 싸이클론은 대기오염물질의 샘플링과 여러 산업공정에서 분진을 제어, 분리하는데 널리 사용되고 있다. 이는 싸이클론의 구조 및 형태가 간단하여, 제작과 운전이 쉽고 비용이 적게 들기 때문이다 하지만 작은 입자에 대한 분리효율이 낮기 때문에 싸이클론의 구조 및 형태를 변화시키거나 싸이클론내에 운전 조건을 변화시켜 높은 분리효율을 얻으려는 연구가 수행되어 왔다. 특히, 싸이클론내에 이중으로 원심력이 작용하게 한 double cyclone(Zhu et al., 2001)과 입자 하전 및 전기장 형성을 위해 고전압을 인가하는 전기싸이클론이(Lim et al., 2001) 최근에 연구가 되어지고 있다. (중략)

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Phase Separation of Lennard-Jones Particles Using Molecular Dynamics and Brownian Dynamics Simulations

  • Jeong, Ji-Yun;Lee, Ju-Min;Kim, Jun-Su
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.169-182
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    • 2014
  • 이 연구에서는 Lennard-Jones (LJ) particle을 이용하여 상분리 현상을 이해하기 위한 컴퓨터 시뮬레이션 연구를 수행하였다. 초기에 균일하게 분포되어 있는 LJ 입자들을 시뮬레이션 하면 상대적으로 dense phase와 dilute phase로 상분리 현상이 일어나게 된다. 상분리 현상의 첫 번째 단계를 핵 생성 (nucleation) 이라고 한다. 본 연구에서는 Brownian Dynamics (BD) Simulation과 Molecular Dynamics (MD) Simulation을 이용하여 상평형 그림을 구하고 초기에 일어나는 LJ 입자들의 nucleation rates를 구하였다.

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Characteristics of Particle Separation in Water Using Lab-Scale Acoustic Standing Wave (실험실 규모의 음향정재파를 이용한 수중의 입자분리 특성)

  • Ahn, Jaehwan;Kang, Sungwon;Ahn, Kwangho;Kim, I tae;Kim, Seog gu;Ahn, Hosang;Lee, Youngsup
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.12
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    • pp.787-791
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    • 2012
  • Characteristics of particle separation in water using labscale acoustic standing wave were studied. Acoustic standing wave is similar to either sound wave or ultrasonic, which makes a constant wave while returning to the origin by reflector. During that time, particulates dispersed in water are collected on the node of wave, where a sound pressure is zero. Acoustic standing wave transducer as of 28.0 kHz and 1.0 MHz were utilized and $6.8{\mu}m$ kaolin and $100.5{\mu}m$ redmud in average diameter were used as experimental materials in water. Once acoustic standing wave are generated in water, water temperature rises by $0.15{\sim}0.20^{\circ}C/min$ due to a sound pressure. Initial concentration of kaolin and redmud were controlled to have same as of 0.1, 0.2, 0.3, 0.4, 0.5 g/L, respectively. Removal efficiency of the turbidity in a reacting chamber after 5 minutes, when acoustic sound wave was formed in most distinct, was measured to have 18.2~56.2% for kaolin and 23.0~53.6% for redmud at 1.0 MHz. Particle separation was not observed at 28.0 kHz.

Characteristic of Water Pervaporation Using Hydrophilic Composite Membrane Containing Functional Nano Sized NaA zeolites (기능성 나노 제올라이트가 분산된 친수성 복합막 제조 및 탈수 투과증발 특성 연구)

  • Oh, Duckkyu;Lee, Yongtaek
    • Korean Chemical Engineering Research
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    • v.51 no.1
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    • pp.98-105
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    • 2013
  • The NaA zeolite particles were dispersed in a poly(vinyl alcohol) (PVA) matrix to prepare a composite membrane. The nano sized zeolite particles of NaA were synthesized in the laboratory and the mean size was approximately 60 nm. Pervaporation characteristics such as a permeation flux and a separation factor were investigated using the membrane as a function of the feed concentration from 0.01 to 0.05 mole fraction and the weight % of NaA particles between 0 wt% and 5 wt% in the membrane. Also, the micro sized particles of $5{\mu}m$ were dispersed in the membrane for a comparison purpose. When the ethanol concentration in the feed solution was 0.01 mole fraction, the flux of water significantly increased from $600g/m^2/hr$ to $2000g/m^2/hr$ as the content of the nano NaA particles in the membrane increased from 0 wt% to 5 wt%, while the NaA particles improved the separation factor from 1.5 to 7.9. When the flux of water through the membrane containing nano sized particles was roughly 15% increased compared to the micro sized particles, whereas the separation factor of water was found to be approximately 5% increased. It can be said that the role of the nano sized NaA particles is quite important since both the flux and the separation factor are strongly affected.