• 펄프종이기술
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• 제33권1호
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• pp.16-23
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• 2001

Hydraulic transport of fines up to the surface of flotation cell was supposed to be a mechanism of fines fractionation through the froth-flotation. Efficient fractionation of fines means efficient skimming out of flotation rejects as much as possible with least long fiber loss. The selectivity of fines fractionation was found to be mainly affected by long fibers flocculation degree in this study. Lack of sufficient flocculation of long fibers could lead to extensive loss of long fibers. It was also found that higher flotation flux caused higher flotation reject as well as the increase of long fiber loss, but did not affect the fine content ratio in the flotation reject. We controlled the flotation flux and the stock consistency, and chose a cationic polymer to maximize the flocculation of long fibers and to increase the amount of flotation reject. The highest efficiency of fines fractionation was obtained at 1.3% of stock consistency and at 100L/min of flotation flux in our experimental set up. The cationaic polymer we chose was found to be very effective in fiber flocculation and flotation froth stabilization. New definitions of fractionation efficiency were introduced in this study to compare the results more clearly.

• 상하수도학회지
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• 제18권6호
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• pp.807-813
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• 2004

Wastewater was treated by two different treatment processes; activated sludge process and advanced wastewater treatment process (KNR process) using lab-scale experiment. Two treated wastewater showed good treatment efficiency of organic matter removal, up to 90% removal. Nitrogen and phosphorus were not effectively removed though activated sludge process, while KNR process showed good removal efficiency of nitrogen and phosphorus; 56% nitrogen removal and 95% phosphorus removal. KNR process showed better removal efficiency of organic matter, nitrogen, and phosphorus compared to activated sludge process. Organic matter characterization was tracked though measurement of UV scan, SUVA, and XAD fractionation. Treated wastewater showed higher SUVA value than wastewater influent, indicting less aromatic characteristic of organic matter. XAD fractionation showed hydrophilic fraction decreased though wastewater treatment, suggesting microbes preferentially digest hydrophilic and aliphatic molecules rather than hydrophobic and aromatic molecules of organic matter.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4291-4296
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• 2011

Gravitational SPLITT fractionation (GSF) provides separation of colloidal particles into two subpopulations in a preparative scale. Conventionally, GSF is carried out in a thin rectangular channel having two inlets and two outlets at the top and bottom of the channel, respectively. And the channel is equipped with two flow-splitters, one between the top and bottom inlets and another between the top and bottom outlets. A large scale splitter-less GSF system had been developed, which was designed to operate in the full feed depletion (FFD) mode. In the FFD mode, there is only one inlet through which the sample is fed, thus preventing the sample dilution. In this study, the effect of the sample-loading (in the unit of g/hr) on the fractionation efficiency (FE, number% of particles in a GSF fraction that have the sizes expected by theory) of the new large scale splitter-less FFD-GSF system was investigated. The system was tested in the sample-loading range of 3.0-12.0 g/hr with polyurethane latex beads (PU) and sea-sediment. It was found that there is an optimum range in the sample-loading for a FFD-GSF separation. It was also found that there is a general tendency of FE decreasing as the concentration of the sample suspension increases.

• 펄프종이기술
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• 제32권4호
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• pp.18-26
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• 2000

In order to investigate the influencing factors in flotation fractionation, flotations were performed at varied conditions. The selectivity of fines fractionation was mainly affected by long fiber flocculation degree and if there were not sufficient flocculation of long fibers, more loss of long fibers could not be avoided. The amount of flotation rejects were totally dependent on the stability of froth floated on the stock surface. Only small size fines could stabilize the froth as they hindered the drainage of liquid lamella in flotation-froth. More flotation reject and better flocculation of long fibers were two important factors for improving flotation. Changing a flotation flux or an air-mixing ratio to increase the flocculation of fibers increased long fiber ratio in the reject. In order to satisfy the both conditions of reducing long fiber loss and of increasing flotation reject, search of fractionation promoter is needed.

• 분석과학
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• 제28권6호
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• pp.453-459
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• 2015

Split-flow thin cell fractionation (SPLITT fractionation, SF)은 밀도와 입자 크기에 따라 입자성 물질이나 거대분자를 연속적으로 분리 및 분획하는 기술이다. SF 모드 중 full-feed depletion mode (FFD)는 오직 한 개의 주입 구를 가지고 있으며, outlet에만 flow stream splitter가 존재한다. SPLITT은 두 가지의 중요 인자가 있다. 하나는 시간에 따라 통과되는 시료의 양 (throughput, TP)과 또 다른 하나는 이론에 의해 예측된 크기를 가지는 입자들의 수 퍼센트로 정의하는 분획효율 (fractionation efficiency, FE)이다.. 기존 FFD 모드에서는 splitter가 outlet에 존재하여, 채널 규모를 확장시키는 데 제한이 있어 시료 처리량의 한계가 있다. 따라서 splitter를 제거하고 채널규모를 증가하여 시료 처리량을 대폭 증가시킬 수 있는 대규모 중력장 FFD-SF 채널을 사용하였다. 따라서 이 논문에서는 대용량 중력장 FFD-SF의 TP와 FE 최적화를 위하여 시료농도와 유속변화로 실험을 진행하였다. 이 실험에서는 두 개의 다른 입자 분포 (3~7 µm, 2~30 µm) 를 가지는 Polyurethane (PU) latex beads가 사용되었다. 시료의 농도는 0.2~0.8% (wt/vol)을 사용하였으며, 채널의 유속은 70~160 mL/min을 사용하였다. 분획된 입자는 광학 현미경으로 확인하여 직접 크기 관찰을 하였으며 시료 회수율 (recovery)은 수집된 입자를 0.1 µm 맴브레인 필터로 거른 후 무게측정으로 실험하였다. 본 연구를 통해 fraction-a의 분획효율 (FE)은 이론에 따라 정확히 맞춰준다면 언제든 좋은 수치를 얻을 수 있다는 것이 확인되었고, 시료의 입자크기가 커서 채널에 쌓일 경우, 시료 회수율을 높이기 위해서는 이동상을 더 흘려주는 방법을 사용하면 효과적인 것을 확인하였다. 또한 효율적인 TP로 실험을 진행하기 위해서는 최소한 0.4% 농도는 사용해야 효율적인 분획이 이뤄진다는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제13권8호
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• pp.3774-3778
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• 2012

Reformate 분리 공정에 대한 열복합 증류탑의 가능한 제어 구조를 조사하고 그 제어 성능을 검토하기 위하여 동적 모사를 수행하였다. Aspen HYSYS를 사용하여 $3{\times}3$ 제어구조를 적용하여 여러 가지 제어구조로 동적 모사한 결과 Reformate 분리 공정 주탑의 상부, 중간, 하부 제품 조성은 각각 reflux flow rate, 주탑에서 전처리탑 상부로 흐르는 liquid draw rate, vapor boilup rate로 제어되는 구조가 가장 운전 안정성이 확보됨을 확인하였다.

• 한국물환경학회지
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• 제38권3호
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• pp.133-142
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• 2022

Natural organic matter (NOM) is a heterogeneous mixture of organic matter with various polarities and molecular weights in an aquatic environment. This study investigated the effects of separation conditions (resin volume, organic matter, etc.) and the repeated use of the resin for the fractionation of organic components in the DAX resin fractionation method. The distribution characteristics of the organic components ((hydrophilic [Hi], hydrophobic acid [HoA], and hydrophobic neutral [HoN]) under the derived fractionation conditions were also analyzed. Constant fractionation results (i.e. HoA/Hi ratio) were obtained in the column capacity factor (i.e. the packed resin volume) in the range of 50 to 100. The resin-packed column maintained constant separation efficiency for up to two repeated uses. The above conditions were applied to wastewater and stream water samples (before and after rainfall). The results showed that the concentration of organic matter in the wastewater effluent was 2-15 times lower with an increased ratio of hydrophilicity to hydrophobicity (i.e. Ho/Hi) compared to the influent depending on the industrial wastewater classification. Particularly, HoN was found to have a high content distribution, 10.2-50.4% of the total dissolved organic matter (DOM), in the effluents. For the stream water, the content of Hi or HoN increased significantly after rainfall, suggesting a correlation with the distribution characteristics of pollutants from the stream watershed. The results provide useful data to enhance the reliability of the DAX resin fractionation and its application to environmental samples.

• 한국축산식품학회지
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• 제38권4호
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• pp.693-702
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• 2018

The purpose of this study was to develop a commercially viable method for synthesis of conjugated linoleic acid (CLA) using the linoleic acid fraction obtained from six pork by-products (liver, lung, heart, stomach, small intestine, and large intestine). The workflow of CLA synthesis from each by-product was as follows: washing${\rightarrow}$crude fat extraction${\rightarrow}$fractionation into saturated and unsaturated fatty acids${\rightarrow}$repeat unsaturated fatty acid fractionation${\rightarrow}$CLA synthesis. Cis-9, trans-11, and trans-10, cis-12 CLA was synthesized from pork by-products. The yield of CLA synthesis of pork by-products ranged from 1.55 to 11.18 g per 100 g of by-products. The amount of synthesized CLA was the highest in the small intestine and large intestine by-products. Fractionation of pork by-products nearly doubled the yield of CLA. We suggest that commercial fractionation methods could increase the yield of CLA at low cost, reduce waste, and improve the efficiency of by-product utilization.

• 펄프종이기술
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• 제32권4호
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• pp.27-33
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• 2000

A new technique for fractionating pulp stock into a long fiber portion and fines fraction was developed by KRICT in order to enhance the drainage and strength properties of recycled OCC pulp. In order to investigate the effect of fines contents in stock and stages of flotation on fractionation efficiency, flotations were performed at varied fines contents and flotation stages. Based on the result of multi-stage flotation fractionation it could be said that fines smaller than 15${\mu}{\textrm}{m}$ stabilize flotation froth of OCC. Although the amounts and the fines contents of flotation reject could be increased by multi-stage flotation fractionation of OCC, flotation stages more than 3 times were found to be inefficient in terms of fines concentrating degree. In order to satisfy the both conditions of reducing long fiber loss and of increasing flotation reject, several kinds of fractionating promoters were searched and investigated. And high molecular weight cationic polyacrylamide was chosen as a long fiber flocculating and flotation froth-stabilizing agent.

• 천문학회보
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• 제36권2호
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• pp.105.1-105.1
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• 2011

We present the modeling results of deuterium fractionation of water ice, $H_2$, and the primary deuterium isotopologues of $H3^+$ in the physical conditions associated with the star and planet formation process. We calculated the deuterium chemistry for a range of gas temperatures (Tgas~10-30 K) and ortho/para ratio (opr ) of $H_2$ based on state-to-state reaction rates and explore the resulting fractionation including the formation of a water ice mantle coating grain surfaces. We find that the deuterium fractionation exhibits the expected temperature dependence of large enrichments at low gas temperature, but only for opr-H2<0.01. More significantly the inclusion of water ice formation leads to large D/H ratios in water ice (${\geq}10^{-2}$ at 10 K) but also alters the overall deuterium chemistry. For T<20 K the implantation of deuterium into ices lowers the overall abundance of HD which reduces the efficiency of deuterium fractionation at high density. Under these conditions HD will not be the primary deuterium reservoir in the cold dense interstellar medium and $H3^+$ will be the main charge carrier in the dense centers of pre-stellar cores and the protoplanetary disk midplane.