• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.233-243
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• 2015

The bimodal flocculation of cohesive sediments in water environments describes the aggregation and breakage process developing a bimodal floc size distribution with dense flocculi and floppy flocs. A two class population balance equation (TCPBE) was tested for simulating the bimodal flocculation by a model-data fitting analysis with two sets of experimental data (low and high turbulent flows) from 1-D flocculation-settling column tests. In contrast to the Single-Class PBE (SCPBE), the TCPBE could simulate interactions between flocculi and flocs and the flocculation mechanism by differential settling in a low turbulent flow. Also, the TCPBE could perform the same quality of simulation as the elaborate Multi-Class PBE (MCPBE), with a small number of floc size classes and differential equations. Thus, the TCPBE was proven to be the simplest model that is capable of simulating the bimodal flocculation of cohesive sediments in water environments and water, wastewater treatment systems.

• Clean Technology
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• v.7 no.1
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• pp.27-34
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• 2001

The waste slurry generated from CMP process contains particulate and heavy metals. It is hard to treat the waste slurry by conventional treatment method because the particulates in the waste are too fine to be easily separated the solid from the waste for the purpose of water recycling. The investigation was focused on finding the optimum condition of coagulation with two different coagulants. When the solid content in the waste slurry solution was 0.1wt%, the optimal ranges of pH and PACl concentration were 4~6 and 20~50 mg/L, respectively. When the solid content was increased to 0.5wt%, the optimal condition was 4~5 for pH and 50~100 mg/L for PACl concentration.

• Korean Journal of Animal Reproduction
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• v.11 no.1
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• pp.42-62
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• 1987

본 실험은 성숙가토의 정자와 정장의 항원성을 조사하여 면역적 불임원인 규명에 필요한 기초자료를 얻고자 시도하였다. 인공질로 채취한 정액을 원심분리하여 얻은 정자와 정장을 항원으로 사용하였으며 항원성의 측정방법은 크로마토그라프에 의한 단백질 분리, SDS-PAGE, HPLC, 한천확산법, 전기영동, 수동적혈구응집방법 및 부동화시험이었다. 얻어진 결과는 다음과 같다. 1. SDS-PAGE 전기영동시 정상가토 정장에서 약 23개의 단백질이 분리되었고, 그중 분자량이 약 20,000되는 단백질부분이 정관절제 수술한 정장에서 나타나지 않았다. 2. 정상가토 정장을 HPLC를 이용한 분석에서 3개의 peaks을 볼 수 있었고, 정관절제수술한 것에서는 peak 1에 해당하는 단백질이 소실되었다. 3. 한천확산시험에서 정상정장은 이종혈청과는 4개의 침강선을 나타냈고, 전기영동에서는 7개의 침강선을 나타냈다. 4. 이종면역에서 정자 및 정장은 항체가 상승이 용이하였지만, 동종면역시는 추가면역이 필요하였으며 개체간의 역가차이를 보였다. 정자면역한 자성가토에서는 수동적혈구응집반응을 나타냈지만, 한천확산 및 전기영동반응은 보이지 않았고, 같은 처치를 받은 웅성가토에서도 역시 같은 반응양상을 나타냈다. 5. 동종 및 이종항혈청을 이용한 교차전기영동방법으로 정장의 항원적 구성요소를 구별할 수 있었다. 사출된 정액에서 분리된 정장은 일부 항원을 포함하고 있었으며 이는 성숙한 정자에서 기인한 것으로 사료되었다.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.607-613
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• 1992

A tower fermentor equipped with a modified settler was used for ethanol fermentation using highly flocculating yeast, Saccharomyces uvarum. The settler was constructed of glass column divided into two chambers by a funnel shaped divider. Gas was allowed to escape from lower chamber of the settler through a small tube. This design significantly reduced the turbulence in upper chamber of the settler and made it possible to operate at high dilution rate. Using the tower fermentor, the effects of operating conditions such as initial glucose concentration, dilution rate and cell recycle ratio were studied. The maximum ethanol productivity, 64.0 g/l' h was obtained at a dilution rate 1.1 h -1 and a cell recycle ratio 5 with the corresponding ethanol concentration of 58.8 g/l, and cell mass of 88 g/l.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.706-712
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• 1999

PSD (particle size distribution) for 2,000 mg/$\ell$ natural loess in seawater showed normal distribution cure at 0 minute settling time, accompanying with very large particle distribution range with its mean particle diameter of 31.6 $\mu$m and coencient of variance of $72.6\%$, With elapsed time it showed that the PSD was rapidly changed from normal distribution cure to abnormal distribution curve, steepened the right-hand side of it and its coefficient of variance was getting increased because of rapid settling of large size particles, Cumulative weight distribution showed that 2,000 mg/$\ell$ natural loess in seawater was almost $100\%$ constituted of particles bigger than 20 $\mu$m in diameter. Ratio of $V_s/(D_{bm})^{1/2}$ for loess particles in seawater was increased with increase of particle size in geometrical progression. Almost all loess particles in seawater had Stokes settling velocity not less than 2,255 times of Brownian diffusion coefficient, There was almost to EDL (about 0.4 nm) around natural loess particles in seawater, Thus, there was always LVDW attractive force between loess particles approaching each other in seawater, and almost no EDL repulsive force. Loess particles were not always in the condition of easy floe formation. Concentration of natural loess in seawater increasing from 400 mg/$\ell$ to 10,000 mg/$\ell$, characteristics of the settling was changed from Type I settling (discrete settling) to Type II settling (flocculation settling). PVD (particle volume distribution) showed that natural loess particles in seawater were largely constituted of two types of particles, such as rapidly settling particles and suspended and dispersed particles for a long time. Amount of the latter was much less than that of the former.

• Journal of Korea Water Resources Association
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• v.49 no.10
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• pp.887-901
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• 2016

Cohesive sediments form flocs through the flocculation process. The size and density of floc are variable whereas those of a fine sediment are always assumed to be constant. The settling velocity, one of main factors of sediment transport, is determined by size and density of particle. Therefore, the flocculation process plays an important role in transport of cohesive sediment. It is of great difficulty to directly measure the density of floc in the field due to technical limitation at present. It is a popular approach to estimate the density of floc by applying the fractal theory. The main assumption of fractal theory is the self-similarity. This study aims to examine the applicability of fractal theory to cohesive sediment in small rivers of Korea. Sampling sediment has been conducted in two different basins of Geum river and Yeongsan river. The results of settling experiments using commercial camera show that the sediment in Geum river basin follows the main concept of fractal theory whereas the sediment in Yeongsan river basin does not have a clear relationship between floc size and fractal dimension. It is known from this finding that the fractal theory is not easily applicable under the condition that the cohesive sediment includes the high content of organic matter.

• KSBB Journal
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• v.7 no.3
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• pp.166-171
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• 1992

Zoogloea ramigera 115 was cultured for biopolymer production and its bioflocculant usages. Cultural conditions of the organism were examined with regard to high production of the microbial polysaccharide. The most suitable medium was found to contain glucose as a carbon source, $NaNO_3$ as a nitrogen source, and yeast extract as an organic nutrient. The initial pH of 6.0 proved to optimal. The biopolymer was extracted effectively using ultrasonication and high speed centrifugation, followed by propanol addition. Jar test results indicate that the polysaccharide produced by the organism is an effective flocculant.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1143-1150
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• 2009

This study was carried out to investigate of aerobic granulation by using sequencing batch reactor(SBR). To make aerobic granular sludge in short period of time, we used polymer. In case of SBR, we have studied on physicochemical characteristics of particle size, settling velocity, surface charge, and specific oxygen utilization rate(SOUR) depending on aerobic particle's formation. The results of running SBR with $5.4kg{\cdot}COD/m^3{\cdot}d$ of COD loading rate and 20 days reaction time showed that aerobic particle size, settling velocity, SOUR, surface charge, polysaccharide/protein(PS/PN) ratio were 2.6 mm, 1.7 cm/s, $346mg{\cdot}O_2/g{\cdot}MLVSS{\cdot}hr,\;(-)0.26{\cdot}meq/g{\cdot}MLVSS$, and 2.06 mg/mg respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5C
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• pp.217-228
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• 2009

In case of application of electrophoresis method for leakage restoration of waste impoundment, main points of consideration were to evaluate the mobility of clay particles by electrophoretic force and capacity of leakage repair in leachate electrolyte system contained with various chemical species. However, the flocculation phenomena of clay particles induced by electrochemical interaction between various chemical species and clay particles would cause the big problems in electrophoresis method. Therefore, a series of laboratory tests such as one-dimensional electrophoresis and gravitational experiments were carried out in order to identify the specific chemical species affected flocculation of clay particles and the range of chemical concentration in leachate. In addition, the characteristics of clay particle behavior with chemical species and concentration range in leachate were analized using the concept of the settling velocity, zeta potential, and electrophoretic velocity.

• Korean Journal of Veterinary Research
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• v.6 no.1
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• pp.10-17
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• 1966

The antigenecity of somatic substances of S. pullorum standard strain and variant strain extracted byheat treatment, acid treatment and their modification, ammonium sulfate saturation (60 per cent), trypsin digestion was tested by indirest hemagglutination test and precipitation test and following results were optained. 1. Teatment at $100^{\circ}C$ for an hour of the bacteria could extract the antigen of S. pullorum standard strain and variant strain which was demonstrable by hemagglutination reaction with the human a group and chicken red blood cell. 2. Trypsin digestion was more enhanced its antigenecity in acid extracted antigen of S. pullorum variant strain compare with the S. pullorum standard strain. 3. The extracted antigenic substances of S. pullorum standard strain existed chiefly in the elicited fraction of precipitate at the treatment of ammonium sulfate saturation and after trypsin digestion, its antigenecity was demonstrated by hemagglutination. 4. At the treatment of ammonium sulfate treatment, did not occur the precipicate in acid extracted antigens of S. pullorum variant strain, however, the heal extracted antigen, positive reactions were obtained in both of the precipitate and supernatant fraction of the S. pullorum variant strain by hemagglutination reaction. After trypsin digestion, these fraction also exhibited positive reactions. 5. Precipitation test also tested dub could not detect in any soft of the antigens.