• Journal of Korean Society for Atmospheric Environment
• /
• v.16 no.1
• /
• pp.1-10
• /
• 2000

The behavior of aerosos due to gravitational coagulation was studied experimentally and numerically. In experimental study, the geometric mean particel size increased as time elapsed in a vertical tube column, while the size decreased when the tube was set horizontally. The particle size distribution was observed to maintain the lognormal form during the coagulation process. Separately, numerical calculations were performed for studying the aerosol behavior under gravitational and Brownian coagulation using the moment method. By comparing the expeimented results with the numerical predictions, the governing mechanism of the aerosol behavior proved to be gravitational coagulation.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.4
• /
• pp.480-486
• /
• 2005

The main goals of this work are to investigate the effect of molecular weight distribution(MWD) and activated carbon adsorption capacity after conventional coagulation and enhanced coagulation. The ozonation was very effective to decompose the NOM to smaller size and to remove molecular smaller than 1,000. The concentration of DOC was reduced 0.25mg/L and 0.56mg/L by the conventional coagulation and the enhanced coagulation, respectively The conventional coagulation was not effective to remove NOM. However, the enhanced coagulation was effective to remove MW bigger than 10,000. The higher MW was shifted to smaller weight by ozonation in the raw water and the after conventional coagulation. After enhanced coagulation the MW had not changed significantly by ozonation. Also, it was observed that the ozone dosage did not have significant impact on MW shifting to smaller size. The adsorption capacity simulated by IAST comparing K values showed that the adsorption capacity was not impacted by ozone doses. There was very strong correlation between MW smaller than 10,000 and the mid- and strongly adsorbable fractions.

• Archives of Plastic Surgery
• /
• v.39 no.2
• /
• pp.150-153
• /
• 2012

Hemophilia B is a rare blood coagulation disorder. Complications such as bleeding and hematoma can cause necrosis of flaps, wound disruption, and the disturbance of wound healing. In particular, guidelines for flap operations in hemophilia B patients have still not been defined, and case reports are rare. We reconstructed the heel of a 41-year-old male hemophilia B patient using a reverse sural artery flap operation. The patient presented with mild hemophilia, having 27% of the normal value of coagulation factor IX. Coagulation and the changing value of the coagulation factor were regularly measured, and 70% of the normal value of coagulation factor IX was maintained through the injection of recombinant coagulation factors and antihemorrhagics. Hematoma developed twice (postoperative day [POD] 5 and POD 7) and in each case the hematoma was removed. Injections of recombinant coagulation factors and antihemorrhagics were continuously administered until postoperative week 2. When the coagulation factors were within normal ranges. In this article, a hemophilia B patient underwent reverse sural artery flap surgery and the healing progress was analyzed. We conclude that higher than baseline levels of coagulation factors are needed for successful healing in reverse sural artery flap surgery.

• Journal of Korean Society on Water Environment
• /
• v.30 no.6
• /
• pp.653-657
• /
• 2014

Effects of $H_2O_2$ addition for fenton oxidation on iron coagulation for treatment of phosphorus species, such as orthophosphate, metaphosphate, pyrophosphate, organic phosphate, were investigated. The effects of coagulant dosage, hydrogen peroxide dosage and the combined sequence ferric coagulation and $H_2O_2$ addition for fenton oxidation and coagulation were studied. The characteristics of floc growth rate were monitored using the PDA. The removal efficiencies of phosphorus species by iron coagulation were increased as Fe/P molar ratio increased. However, the removal efficiencies of metaphosphate, pyrophosphate, organic phosphate by a ferric coagulation were not increased as Fe/P molar ratio increased. The removal efficiency of metaphosphate, pyrophosphate, organic phosphate was increased by using iron coagulation and $H_2O_2$ addition for fenton oxidation. The result indicated that non-reactive phosphorus after iron coagulation was changed to reactive phosphorus by $H_2O_2$ addition for fenton oxidation and the oxidized iron enhanced the coagulation efficiencies.

• Food Science of Animal Resources
• /
• v.30 no.4
• /
• pp.551-559
• /
• 2010

Among the food constituents, proteins differ in coagulation properties as compared to other constituents in food system. Especially milk protein coagulate through different pathways thus this coagulability can be used for manufacture of various dairy products or as a determinant of dairy product analysis. These milk coagulation methods include organic solvent, isoelectric point, trichloroacetic acid, Ca-sensitive casein, heavy metal ion and rennet coagulation. The coagulation experiment was performed using above parameters at $0^{\circ}C$ and $25^{\circ}C$ to find the dehydration conditions before coagulating for precheese powder making. After different chemical treatments, there was no coagulation at $0^{\circ}C$ rather at $25^{\circ}C$ whatever the mode of coagulation methods was. The appearance of precipitate with coagulation methods was quite different from above mentioned methods of coagulation illustrated by scanning electron microscope. These powders were used for fabrication of camembert cheese by renneting coagulation at $0^{\circ}C$, showing the possibility of cheese materials and of food additives for fabrication of products.

• Journal of Korean Society of Water and Wastewater
• /
• v.33 no.6
• /
• pp.413-420
• /
• 2019

Pretreatment system of desalination process using seawater reverse osmosis(SWRO) membrane is the most critical step in order to prevent membrane fouling. One of the methods is coagulation-UF membrane process. Coagulation-UF membrane systems have been shown to be very efficient in removing turbidity and non-soluble and colloidal organics contained in the source water for SWRO pretreatment. Ferric salt coagulants are commonly applied in coagulation-UF process for pretreatment of SWRO process. But aluminum salts have not been applied in coagulation-UF pretreatment of SWRO process due to the SWRO membrane fouling by residual aluminum. This study was carried out to see the effect of residual matal salt on SWRO membrane followed by coagulation-UF pretreatment process. Experimental results showed that increased residual aluminum salts by coagulation-UF pretreatment process by using alum lead to the decreased SWRO membrane salt rejection and flux. As the salt rejection and flux of SWRO membrane decreased, the concentration of silica and residual aluminum decreased. However, when adjusting coagulation pH for coagulation-UF pretreatment process, the residual aluminum salt concentration was decreased and SWRO membrane flux was increased.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.5
• /
• pp.689-695
• /
• 2004

Electrocoagulation has been suggested as a promising alternative to conventional coagulation. The process is characterized by reduced sludge production, no requirement for chemical use, and ease of operation. However, this coagulation has scarcely been studied in water purifying process. This study was performed several batch experiments to compare turbidity removal between electrocoagulation and chemical coagulation. In addition, characteristics of floe were evaluated with zeta potential and particle size distributions. Electrocoagulation showed a relatively higher removal of turbidity (approximately 5%) with the same aluminum amount than conventional chemical coagulation. In addition, turbidity removal by electrocoagulation was less sensitive to pH and was greater for more extensive pH range than chemical coagulation. The results of zeta potential and floc size distributions illustrated that electrocoagulation provided the preferable conditions for coagulation such as zeta potential close to zero millivolt and increased portions of particles in the range of 40 and $100{\mu}m$.

• Neonatal Medicine
• /
• v.18 no.1
• /
• pp.1-5
• /
• 2011

Coagulation involves the regulated sequence of proteolytic activation of a series of proteins to achieve appropriate and timely hemostasis in an injured vessel. In the non-pathological state, the inciting event involves exposure of circulating factor VIIa to extravascularly expressed tissue factor, which brings into motion the series of steps which results in cell based model of coagulation. In the new concepts of coagulation system, initiation, amplification and propagation steps are involved to converse of fibrinogen to fibrin. The precisely synchronized cascade of events is counter-balanced by a system of anticoagulant mechanisms. Developmental hemostasis refers to the age-related changes in the coagulation system that are most marked during neonate and childhood. An understanding of these changes in crucial to the accurate diagnosis of hemostatic abnormalities in neonate and children. This review aims to elucidate the main events within the coagulation cascade as it is currently understood to operate in vivo, and also a short review of the anticoagulants as they relate to this model. Also this paper describes the common pitfalls observed in the clinical data related to the coagulation system in neonate to children.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.3
• /
• pp.443-451
• /
• 2012

Wastewater treatment plants need to reduce phosphorus in order to meet increasingly stringent regulations on phosphorus. This study evaluated the feasibility of dolomite as a coagulation aid to enhance phosphorus removal from secondary treated wastewater by chemical coagulation. Standard jar tests were conducted to evaluate the effect of dolomite addition on a coagulation process for phosphorus removal and to determine the optimum doses of coagulants and dolomite. Coagulants used with dolomite yielded a significant improvement in phosphorus removal and reduced total phosphorus concentrations below 0.02 mg/L in wastewater effluent. Dolomite has played an important role in enhancing phosphate adsorption and increasing pH, as a coagulation aid. The maximum removal efficiency of phosphorus in this study was yielded at 25 mg/l of dolomite and 20 mg Al/L of PAC dose. However, considering economic aspects, the optimum doses of dolomite and PAC were 10 mg/L and 15mg Al/L, respectively. Consequently, dolomite, a coagulation aid, can be used in coagulation processes to enhance the removal of phosphorus.

• Journal of Environmental Health Sciences
• /
• v.29 no.2
• /
• pp.1-6
• /
• 2003

This paper reports on a pilot scale comparison of PACS coagulation with and without pH preadjustment. The pH of the water was adjusted with carbon dioxide and sulfuric acid. Process performance was assessed on the basis of total organic carbon(TOC), UV absorbance, turbidity and disinfection by-product(DBP) precursors. Coagulation pH appeared to be a determining factor for maximum NOM removal. The optimum coagulation pH in order to decrease TOC and turbidity were pH 7. Preadjustment of pH 7 increased TOC removal to as much as 43, 47 percent with sulfuric acid and carbon dioxide. Moreover, coagulation at pH 7 caused a reduction in UV$_{254}$, THMFP and HAAFP compared to the baseline coagulation. For preadjustment of pH 7 with carbon dioxide, the percentage of TOC, UV$_{254}$, THMFP and HAAFP shows the reduction rate of 3.8, 0.5, 4.8, 9.4％ comparing to the coagulation rendition using sulfuric acid. Acid addition to depress pH during coagulation decrease Langelier Saturation Index(LSI), potentially causing increase corrosion in water distribution systems. LSI for carbon dioxide and sulfuric acid at pH 6 was -2.3, -3.3. Therefore, carbon dioxide was more effective at controlling corrosion than sulfuric acid.