• Membrane Journal
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• v.11 no.2
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• pp.89-95
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• 2001

Polysulfone membranes containing an inorganic fluor, cerium activated yttrium silicate (CA Y5), were prepared via the phase inversion technique. The casting solutions with the fluor' were solidified to result in a membrane by using two different nonsolvent coagulants, water and isopropanol. In the process, the fluor worked as a monitioring agent for investigating the characteristics of the phase inversiun process. On the initial contact with water as nonsolvent, the induction of rapid polymer collapse results.in the entrapment of the fluor in the formed membrane structure. Impregnated fluor is dispersed in the polymer structure rather than being enveloped by polymer molecules. In comparison, the fluor is localized in the cell-like structure of membrane, as the cast solution film is cuagulated by immersion into a isopropanol bath.

• Journal of Environmental Science International
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• v.20 no.6
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• pp.767-773
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• 2011

The objectives of this research are to investigate the proper coagulation conditions which are a type and doses of coagulants, mixing conditions (velocity gradients and mixing times), pH and so on through Jar-test, to evaluate the flux variations, permeate, backwashing according to characteristics of pretreatment of the wastewater by means of MF membranes for river maintenance water reuse. The effluent water from B-city K-sewage treatment plant are used for this research. Turbidity and suspended solids(SS) are 14.2 NTU and 10.4 mg/L respectively. This condition causes fouling for membrane process. The flux decline could be reduced when coagulation pretreatment was carried out. Optimal coagulations PAC which are commonly used in the sewage treatment plant was observed in this research. The results indicate that an optimal coagulation dose and pH are 80 ppm and pH of 7 respectively, but coagulation efficiency was lower at strong acid or strong base. Results showed that continuous and steady operations in membrane separation process by means of the effective removal of organic matter and turbidity with coagulation pretreatment of sewage secondary effluent were achieved.

• Nuclear Engineering and Technology
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• v.8 no.2
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• pp.69-76
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• 1976

This experiment has been carried out for the removal of long-lived radioactive-nuclides (Sr-90, Ru-106, Cs-137 and Ce-144) contained in the low-level radioactive effluents from the spent fuel reprocessing plant and nuclear power plant, in order to determine the decontaminability of various chemical coagulants and domestic clay mineral (montmorillonite). Phosphate process showed prominent efficiency for the removal of Ce-144, and lime-soda process did good removal efficiency for Sr-90. About Cs-137 copper-ferrocyanide process is much desirable. In phosphate or lime-soda process, most favorable removal efficiency was obtained at more than pH 11. The montmorillonite treated with sodium chloride showed a considerable improvement in the removal of the radioactive-nuclides. By a combined chemicals-montmorillionite process, the radioactive-nuclides could be more effectively removed than by the only chemicals process.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.21-28
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• 2005

The training and prediction modeling using an artificial neural network was implemented to predict the turbidity of treated water as well as to estimate the optimized feed concentration of polyaluminium chloride (PACl) in a water treatment plant. The parameters used in the input layers were pH, temperature, turbidity and alkalinity, while those in output layers were PACl and turbidity of treated water. Levenberg-Marquadt method of feedforward back-propagation perceptron in the neural network toolbox of MATLAB program was used in this study. Correlation coefficients of the training data with the measured data were 0.9997 for PACl and 0.6850 for turbidity and those of the testing data with measured data were 0.9140 for PACl and 0.3828 for turbidity, when four parameters at input layer, 12-12 nodes each at both the first and the second hidden layers, and two parameters(PACl and turbidity) at output layer were used. Although the predictability of PACl was improved, compared to that of the previous studies to use the only coagulant dose as output layer, turbidity in treated water could not be predicted well. Acquisition of more data through several years obtained with the advanced on-line measuring system could make the artificial neural network useful and practical in actual water treatment plants.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.331-336
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• 2004

The correlation between polymeric aluminum species of coagulant and its coagulation efficiency was investigated using several commercial polymeric Al(III) inorganic coagulants (Poly Aluminum Hydroxy Chloro Sulfate 2020 (PAHCS2020), Poly Aluminum Hydroxy Chloro Sulfate 2500 (PAHCS2500) which was introduced in Korean water treatment plants. The poly aluminum chloride (PAC), Poly Aluminum Hydroxide Chloride Silicate (PACS)) and the aluminum salts ($AlCl_3$, Alum ($Al_2(SO_4)_3$)) were used for the purpose of comparison. The comparison of the coagulation efficiency of each coagulant was made by turbidity removal through the standard jar testing procedure and the determination of the hydrolytic Al(III) species was made by the ferron method which can differentiate the monomeric aluminum species from the polymeric aluminum species. Overall, PAHCS2020 and PAHCS2500 showed the better performance in turbidity removal than the aluminum salts. The performance of coagulation was even better without adjustment of pH during the coagulation experiment. The positive correlation between polymeric aluminum species of coagulant and coagulation efficiency was found.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.463-474
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• 2010

In this study, chemical coagulation conditions for treating combined sewer overflow(CSO) occurred during rainy season were evaluated by jar tests with aluminum sulfate[$Al_2(SO_4)_3{\cdot}17H_2O$] and ferric chloride[$FeCl_3{\cdot}6H_2O$]. The raw domestic sewage sampled from the primary sedimentation tank at a local sewage treatment plant was filtered through $150{\mu}m$ sieve before using. Point of zero charge(PZC) for various dose of aluminum sulfate occurred at pH 5.8-6.5, while for ferric chloride occurred at pH 5.3-6.0 in term of streaming current(SC) values. Charge neutralization ability of aluminum sulfate was bigger than that of ferric chloride. Optimum pH and dose of aluminum sulfate and ferric chloride were 6.2, 0.438mM and 5.8, 0.925mM, respectively. Removal efficiencies of TCOD, turbidity, SS and TP were 75, 97, 95, 96% with aluminum sulfate and 74, 96, 98, 99% with ferric chloride at their optimum coagulation conditions. More efficient removal of SS, TP and small particles was possible with ferric chloride at optimum coagulation conditions. Both SC values and COD removal started to increase where soluble phosphorus was completely removed.

• Textile Coloration and Finishing
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• v.14 no.2
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• pp.40-50
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• 2002

In order to remove the pollutants effectively in the dye wastewater by chemical precipitation process, coagulation arid flocculation test were carried out using several coagulants on various reaction conditions. It was found that the Ferrous sulfate was the most effective coagulant for the removal of disperse dye(B79), and we could get the best result lot the removal of disperse dye(B56) in the aspects of TOC removal efficiency and sludge field. When the Ferrous sulfate dosage was $800mg/\ell$, the sludge settling velocity was very fast>, and the color was effectively removed in the disperse dye(B79) solution. Although the color removal was ineffective when the Alum was used as a coagulant, the sludge field was decreased in comparison with the Ferrous sulfate or the Ferric sulfate was used in the disperse dye(B56) solution. The general color removal effect for the disperse dye(B56 and B79) solutions, the Ferric sulfate was more proper coagulant than the Alum. It was showed that TOC removal was improved 5% and over by the addition of Calcium hydroxide, and $30mg/\ell$ of sludge yield was decreased(B79). When Alum or Ferric sulfate was used as a coagulant, pH condition for most effective color removal was 5 in B56 solution. In case of Ferrous sulfate as a coagulant, most effective pH condition for color removal was 9. When Ferric sulfate or Ferrous sulfate was used as a coagulant, pH condition for most effective color removal was 9 in B79 solution.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.4
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• pp.397-406
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• 2009

This study was conducted to monitor the floc sizes forming in the mixing zone in the water treatment plant. The dosing amount of poly aluminium chloride(PAC) was determined by particle dispersion analyzer(iPDA) in the lab and field scale test. During a field test period, PAC coagulant was used and the raw water was taken from Nakdong river. PAC wad diluted to activate the coagulant, leading to bring the more homogeneous dispersion in the shorter time. To monitor the floc sizes, the unit of floc size index(FSI) was used. With increasing of raw water turbidity, FSI value was increased. Also, the increased dosing amount of PAC brought the increased FSI and with overdosing of coagulant was in turn decreased. When the PAC was fed into the raw water after dilution in a field scale test, the width of FSI was narrower compared with the feeding of the mother liquor of PAC, implying that the formed flocs are denser and more uniform sizes. The width of FSI in average was varied on depending on the basicity of coagulant. Also, dF value, fractal dimension was evalued with the different coagulants, showing from 2.01 to 2.03. On-line floc monitor was effective for the optimal dosing in the drinking water plant.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.38-43
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• 2013

ETA (ethanolamine), a pH control agent, has been used as an ammonia substitute in the secondary system of nuclear power plants since 2001. It is impossible to remove ETA from the wastewater treatment system in the nuclear power plant operating currently, because it is the non-biodegradable organics in terms of the environmental. The optimum process and chemicals for the removal of chemical oxygen demand (COD) & N with the field sample were investigated. More than 95% of Ammonium ions, contained much in wastewater, was removed with a diffused aeration system. COD could be removed over 90% through the process that includes the oxidation with mixed peroxidants (sodium persulfate/sodium percarbonate) followed by the physicochemical treatment with coagulants.

• Archives of Reconstructive Microsurgery
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• v.22 no.1
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• pp.38-41
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• 2013

A 31-year-old female patient presented with a skin and soft tissue defect measuring $8{\times}6cm$ in size with exposure of the extensor hallucis longus tendon and the first metatarsal bone after metatarsal lengthening for brachymetatarsia. The defect was covered with a distally based dorsalis pedis flap based on the distal communicating branch of the dorsalis pedis artery. Secondary defect was covered by a split thickness skin graft. There was congestion of the flap tip after the operation; however, it was resolved using medical leeches and anti-coagulants. No necrosis or infection was encountered and the contour of the flap was satisfactory. There was no donor site morbidity. Reverse dorsalis pedis flap has not been commonly used due to the anatomical variation and uncertainty, which is different from the reverse radial forearm flap. However, when faced with the challenge of a moderate soft tissue defect of the distal forefoot, we believe that the reverse dorsalis pedis flap offers a good option with various advantages.