• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.112-118
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• 2012

Fine suspended solids from mine drainage draw attentions due to their potential adverse influences on the water quality, such as increasing turbidity and degrading aesthetic landscape. Currently, sand filter beds are adapted in some mine drainage treating systems. However, more efficient system is in demand, as the existing sand beds reveal some problems, such as frequent maintenance intervals. Various filtering mediums including fly ash, mine tailing aggregates and the sand were tested for improving the current system, using column experimental set-up. Mine drainage samples were collected from the current treating systems in the abandoned H coal mine. The experiment was run for 7 days. Suspended solids recorded as 100.9 mg/L and the value exceeds the current standard, 30 mg/L. Sand was proved to still be the optimum medium for the fine suspended solids, compared to fly ash and fly ash + sand. Mine tailing aggregates were placed at the exit of the columns, substituting gravels. The tailing aggregates is made by mine tailings and clay. Sand bed filters can also be improved by mixing granular activated carbon, which was found to be economical and efficient in the batch experiment, conducted at the same time.

• Journal of Soil and Groundwater Environment
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• v.16 no.3
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• pp.17-27
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• 2011

Recently, a physically based model of water-table fluctuation due to precipitation is developed based on aquifer water balance model. In the model, it was assumed that the water infiltration into ground surface is advection dominant and immediately reaches to water-table. The assumption may be suited for the sites where the water-table is shallow and/or the permeability of the unsaturated zone is high. However, there are more cases where the model is not directly applicable due to thick and low permeable unsaturated zone. For the low permeability unsaturated zone, the pattern of water flux passing through unsaturated zone is diffusive as well as advective. In this study, to improve the previously developed water-table fluctuation model, we combined the delayed drainage model, which has long been used in well hydraulics, to the water-table fluctuation model. To test the validity of the development, we apply the developed model to 5 different domestic sites. The model parameters are calibrated based on the groundwater hydrograph and the precipitation time series, and the correlation analyses among the parameters are pursued. The overall analyses on the delineated model parameters indicate that the delayed drainage parameters or delay index used in the developed model are able to reveal drainage information in the unsaturated zones.

• Journal of Chest Surgery
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• v.19 no.4
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• pp.744-749
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• 1986

Even in the hands of the expert endoscopists, an occasional instrumental perforation of the esophagus occurs. But instrumental perforation of the esophagus should not be difficult to diagnose if the possibility is borne in mind. Occasionally patient with esophageal perforations show little reaction at first, but usually they develop systemic manifestation if surgical management is delayed. Early surgical drainage of esophageal perforation is very important & effective therapeutic method. The delayed surgical treatment of esophageal perforation would have increased the morbidity & mortality by allowing mediastinitis & empyema thoracis. We have experienced 6 cases of delayed surgical management of instrumental perforation of esophagus from May 1974 to April 1986 in the department of thoracic and cardiovascular surgery, Yonsei University, college of the medicine. The ages ranged from 4 years to 57 years. The underlying esophageal diseases consisted of esophageal stricture in 3 cases, foreign bodies in the esophagus in 2 cases and esophageal ca. in one case. Most clinical manifestations on admission were high fever, chest discomfort, chest pain, dysphagia and subcutaneous emphysema. Most complications due to esophageal rupture were acute mediastinitis with or without empyema thoracis. Failure to diagnose promptly and failure to promptly institute adequate treatment undoubtedly were largely responsible for this patients death. All 6 patients had been taken delayed surgical drainage more than 24 hours following esophageal perforation. One patient had been in the open drainage state for long time and the another patient has been in the tracheostomy with postintubation vocal cord ulceration. The third patient died due to respiratory failure and sepsis due to fulminant mediastinitis & empyema thoracis. Even if the patients with esophageal perforation have been taken delayed surgical management, the patients should be survived with aggressive & effective surgical drainage with intensive post-operative care.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5363-5368
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• 2014

This study examined contribution rate on the Soyangho Lake watershed based on the flow regime, and seasonal change was evaluated by calculating the delivery pollution load of the drainage area of Soyangho Lake watershed. According to the contribution rate of the drainage area by the flow regime change, Inbukcheon Creek watershed's SS and T-P entry have recorded abnormal Six month flow and a contribution rate of 46% and 51% during the Low-water flow period. At the same time, the T-P recorded a 49.5% contribution rate and a contribution rate of 48.5% during the Low-water flow period. In sequence, Inbukcheon creek's SS entry recorded a comparatively higher contribution rate than the other drainage area, which are 39.6% and 44.3% during the entire season and 53.8% for T-P, as a result of observing the contribution rate based on the seasonal changes. The T-N at the Naerincheon Creek watershed for the entire season recorded a contribution rate between 39.6% and 44.3%. Overall, Inbukcheon Creek watershed's SS and T-P entry and Naerincheon creek's T-N had a high contribution rate on contaminant spill.

• Archives of Plastic Surgery
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• v.47 no.2
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• pp.140-145
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• 2020

Background Capsular contracture is a common complication of two-stage expander/implant breast reconstruction. To minimize the risk of this complication, capsulectomy is performed using monopolar cautery or ultrasonic surgical instrumentation, the latter of which can be conducted with a Harmonic scalpel. To date, there is disagreement regarding which of the two methods is superior. The purpose of this study was to compare postoperative outcomes between a group of patients who underwent surgery using a Harmonic scalpel and another group treated with monopolar cautery. Methods A retrospective chart review was conducted of patients who underwent capsulectomy as part of two-stage breast reconstruction between January 2018 and February 2019 and who received at least 1 month of follow-up after surgery. Operative time and postoperative outcomes, including drainage duration, were analyzed. Results In total, 36 female patients underwent capsulectomy. The monopolar group consisted of 18 patients and 22 breasts, while the Harmonic scalpel group consisted of 18 patients and 21 breasts. There was no statistically significant difference in demographics between the two groups. The Harmonic scalpel group had a significantly shorter mean drainage duration (6.65 days vs. 7.36 days) and a smaller mean total drainage volume (334.69 mL vs. 433.54 mL) than the monopolar cautery group (P<0.05). No statistically significant difference was observed with regard to seroma or hematoma formation. Conclusions The Harmonic scalpel approach for capsulectomy reduced the total drainage volume and drainage duration compared to the monopolar cautery approach. Therefore, this approach could serve as a good alternative to electrocautery.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.695-701
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• 2020

This study aimed to monitor a pilot-scale vertical flow reactor (VFR) system being operated in long-term for water quality control of pH-neutral mine drainage containing Fe, Mn and As, discharged in D mine site. The treatment systems of VFR and zero manganese reactor (ZMR) consisted of sand/limestone, and steel slag/limestone, respectively. The systems were operated during about six months in order to evaluate their long-term treatment efficiency It was observed that both pH and alkalinity of mine drainage were remarkably increased and more than 98% of Fe, As and Mn ions was continuously removed during the tested period of time. In conclusion, the field results of this work demonstrated that the vertical flow reactor system can effectively treat mine drainage contaminated by Fe, As and Mn.

• Journal of Chest Surgery
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• v.50 no.6
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• pp.477-478
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• 2017

• KCID journal
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• v.2 no.1
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• pp.101-107
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• 1995

• Journal of the Korean GEO-environmental Society
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• v.8 no.3
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• pp.59-65
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• 2007

Excess pore pressures in low permeability soils may not dissipate quickly enough and decrease the effective stresses inside the soil, which in turn may cause a reduction of the shear strength at the interface between the soil and the reinforcement in MSE walls. For this condition the dissipation rate of pore pressures is most important and it varies depending on wall size, permeability of the backfill, and reinforcement length. In this paper, a series of numerical analysis has been performed to investigate the effect of those factors. The results show that for soils with a permeability lower than $10^{-3}cm/sec$, the consolidation time gradually increases. The increase in consolidation time indicates the decrease in effective stress thus it will result in decrease in pullout capacity of the reinforcement as verified by the numerical analyses. It is also observed that larger consolidation time is required for longer reinforcement length (longer drainage path).

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.748-755
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• 2007

To develop an efficient pump operating rule for a retard basin, it is necessary to estimate inflow to the retard basin accurately which is affected by the backwater effect at the outlet of the conduit. The magnitude of the backwater effect is dependent on the water depth of a retard basin; however, the depth is determined by the amount of inflow and outflow. Thus, a real time simulation system that is able to simulate urban runoff and the pump operation with the consideration of the backwater effect is required to estimate the actual inflow to a retard basin. With this system, the efficient pump operating rule can be developed to diminish the possible flood damage on urban areas. In this study, a realtime simulation system is developed using the SWMM 5.0 DLL and Visual Basic 6.0 equipped with EXCEL to estimate inflow considering the backwater effect. The realtime simulation can be done by updating realtime input data such as minutely observed rainfall and the depth of a retard basin. Using those updated input data, the model estimates actual inflow, the amount of outflow discharged by pumps and gates, the depth of each junction, and flow rate at a sewer pipe on realtime basis. The developed model was applied to the Joonggok retard basin and demonstrated that it can be used to design a sewer system and to estimate actual inflow through the inlet sewer to reduce the inundation risk. As results, we find that the model can contribute to establish better operating practices for the pumps and the flood drainage system.