• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.1
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• pp.13-24
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• 1986

A real-time hourly operation model for the flood control of Soyanggang Dam and Hwachon Dam, which are located in the North Han River is developed. The method is based on simulation with a feedforward-feedback control. The feedforward control was mainly concerned with providing the release history from the single dams. The outflows from the single dam operation rules with forecasted inflows were used as the inputs to simulation. And then feedback control is applied to reduce the peak discharge at the junction. Also, sensitivity analysis of the operation model was provided to respect the temporal and spatial distribution of storms to the model.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.651-658
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• 2008

Estuary barrier is a hydraulic structure constructed to supply safely water as protecting chlorine penetration of sea water. However, the barrier brings about a problem which decreases original functions of estuary because hydraulic ecology was disrupted as obstructing natural water exchange between fresh water and sea water. It is important to supply Enough fresh water in the estuary ecosystem. But it is possible to reduce the problems brought from barrier throughout efficient water gate operation of estuary barrier. It was shown in this study that the environmental effect of estuary in Nakdong river was investigated according to the control of water level. Also, the basic information about the effective water gate operation was provided. The analysis results showed that the release rate of estuary was increased about 20% as changing the operational water levels. This helps supplying fresh water durably to the mixing zone. Also, CE-QUAL-W2 model was utilized to assess water quality. The values of BOD and COD were not changed in estuary area. From the result, it was analyzed the effect of water quality according to the water gate operation was not indicated.

• Journal of Ecology and Environment
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• v.38 no.2
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• pp.271-279
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• 2015

After the reversion of Okinawa (Ryukyu Islands) to Japan in 1972, extensive urban and agricultural development resulted in a significant increase in sediment discharge to coastal waters. The release of sediment has caused the degradation of freshwater and coastal ecosystems and biodiversity. A consideration for catchment-to-reef continua, as well as agricultural (socioeconomic) factors is necessary to establish proper land-based management plans for the conservation of the island environment. We have set up a framework to integrate biophysics and socioeconomics: 1) setting a conservation target and threshold, 2) identifying the sources and processes, and 3) examining cost-effectiveness and management priorities. The framework may be applicable to other tropical and subtropical islands with similar characteristics.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.4
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• pp.1143-1151
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• 2016

To study the dispersion process and residence time of anthropogenic pollutant in Masan bay, a three-dimensional hydrodynamic model coupled to a particle tracking model, EFDC, is applied. Particle tracking model simulated the instantaneous release of particles emulating discharge from river and wastewater treatment plant to show the behaviour of pollutant in terms of water circulation and water exchange. Modelled outcomes for water circulation were in good agreement with tidal elevation and current data. The results of particle tracking model show that over half of particles released from northern Masan bay transport to out of area while the particles from Dukdong wastewater treatment plant transport to northern area. This meant pollution source from inside and outside of the northern area can affect water quality of northern Masan bay.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.24-30
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• 2019

This study investigated the heat dissipation characteristics of a heat-sensitive LED. The results of the empirical test showed that the best temperature intensification was found at 90 with 15-fins, and the heatsink installed perpendicular to the direction of the flow of air was directly connected to the air in the largest heat shield area, leading to the best cooling, and the number of fin also resulted increase in the heat discharge area, resulting in the largest cooling action with 15 fins. It was found that the rate of air flow changed in the range of 1.5m/s to 2.5m/s, but only by a deviation of about $2^{\circ}C$ to $3^{\circ}C$ from the current state of 15 fins at 2.5m/s, and the rate of air flow increased, but the performance of the heat release was not significantly increased. As a result wind speed with minimum air flow conditions of 1.5m/s can greatly contribute to the heat dissipation performance.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1434-1443
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• 2019

Although chemical oxygen demand (COD) is an important issue for wastewater treatment, COD reduction with microalgae has been less studied compared to nitrogen or phosphorus removal. COD removal is not efficient in conventional wastewater treatment using microalgae, because the algae release organic compounds, thereby finally increasing the COD level. This study focused on enhancing COD removal and meeting the effluent standard for discharge by optimizing sludge inoculation timing, which was an important factor in forming a desirable algae/bacteria consortium for more efficient COD removal and higher biomass productivity. Activated sludge has been added to reduce COD in many studies, but its inoculation was done at the start of cultivation. However, when the sludge was added after 3 days of cultivation, at which point the COD concentration started to increase again, the algal growth and biomass productivity were higher than those of the initial sludge inoculation and control (without sludge). Algal and bacterial cell numbers measured by qPCR were also higher with sludge inoculation at 3 days later. In a semi-continuous cultivation system, a hydraulic retention time of 5 days with sludge inoculation resulted in the highest biomass productivity and N/P removal. This study achieved a further improved COD removal than the conventional microalgal wastewater treatment, by introducing bacteria in activated sludge at optimized timing.

• The Journal of Korean Medicine
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• v.41 no.4
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• pp.106-111
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• 2020

Objectives: Hepatitis A is a typical acute hepatitis caused by hepatovirus, and then most patients recover easily without progression to chronic condition. However, certain cases have the risk of severe symptoms or even death. This case report presented a hepatitis A accompanied with pancreatitis, which had been completely recovered in a Korean medicine hospital. Case presentation: A 38-year woman had felt the malaise, mild chilling, muscle pain and abdominal discomfort for 10 days, which led her visit doctors and took anti-pyretic analgesics and digestants. The symptoms, especially epigastric pain and fatigue, became worse, and then she hospitalized in a Korean medicine hospital. Based on the drastic elevations of hepatic enzymes (aspartate transaminase 1,604 IU/L and alanine transaminase 2,825IU/L) with an anti-HAV IgM positive, she was diagnosed with hepatitis A. After bed rest and herbal drug treatment (CGX and Innae-Tang) for 5 days, the laboratory abnormalities and subjective symptoms had been improved gradually, except the upper gastric discomfort and pain. Those symptoms had anticipated the comorbidity with HAV-induced pancreatitis, supported by the high level of serum lipase release. Another 5-day hospitalized treatment improved all subjective symptoms and then the laboratory results were completely normalized including detection of anti-HAV IgG within 15 days after discharge. Conclusion: This study presented a typical hepatitis A accompanied with pancreatitis, which should be considered in diagnosis and management of hepatitis A.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.106-116
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• 2021

To secure basic data by monitoring the growth of salmon (Oncorhynchus keta) released to the Taehwa River. After discharge, the characteristics of the young salmon distribution and migration rate habitat were investigated for two years. A total of 4 points [Sunbawi bridge (St.1), Guyeong bridge (St.2), Samho bridge (St.3), and Myeongchon bridge (St.4)] were investigated. The survey of 2017 indicating an increase of 10 mm in average length and 0.8 g in average weight, and the survey of 2018 indicating an increase of 10 mm in average length and 0.5 g in average weight. Among 39 species, 10 insectivorous and 12 omnivorous, are believed to compete with young salmon for food. 6, 5, 6 and 8 predatory fish species has emerged at each site, respectively. According to this study, it is believed that St.1 and St.2 points are more proper as discharge location of young salmon because these two points have less varied in depth, flow rate, salt concentration etc. In addition, it is thought that the night or dawn time in early January is the best discharge time of young salmon fish because predatory fish such as Korean piscivorous chub and bass etc. does not eat food actively at that time.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.99-110
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• 2023

Non-point source (NP) pollutants in an agricultural landuse are discharged from a large area compared to those in other land uses, and thus effective source control measures are needed. To develop appropriate control measures, it is necessary to quantify discharge load of each source and evaluate the degree of water quality improvement by implementing different options of the control measures. This study used Hydrological Simulation Program-FORTRAN (HSPF) to quantify pollutant discharge loads from different sources and effects of different control measures on water quality improvements, thereby supporting decision making in developing appropirate pollutant control strategies. The study area is the Gyeseong river watershed in Changnyeong county, Gyeongsangnam-do, with agricultural areas occupying the largest proportion (26.13%) of the total area except for the forest area. The main pollutant sources include chemical and liquid fertilizers for agricultural activities, and manure produced from small scale livestock facilities and applied to agriculture lands or stacked near the facilities. Source loads of chemical fertilizers, liquid fertilizers and livestock manure of small scale livestock facilities, and point sources such as municipal wastewater treatment plants (WWTPs), community WWTPs, private sewage treament plants were considered in the HSPF model setup. Especially, NITR and PHOS modules were used to simulate detailed fate and transport processes including vegitation uptake, nutrient deposition, adsorption/desorption, and loss by deep percolation. The HSPF model was calibrated and validated based on the observed data from 2015 to 2020 at the outlet of the watershed. The calibrated model showed reasonably good performance in simulating the flow and water quality. Five Pollutants control scenarios were established from three sectors: agriculture pollution management (drainge outlet control, and replacement of controlled release fertilizers), livestock pollution management (liquid fertilizer reduction, and 'manure management of small scale livestock facilities) and private STP management. Each pollutant control measure was further divided into short-term, mid-term, and long-term scenarios based on the potential achievement period. The simulation results showed that the most effective control measure is the replacement of controlled release fertilizers followed by the drainge outlet control and the manure management of small scale livestock facilities. Furthermore, the simulation showed that application of all the control measures in the entire watershed can decrease the annual TN and TP loads at the outlet by 40.6% and 41.1%, respectively, and the annual average concentrations of TN and TP at the outlet by 35.1% and 29.2%, respectively. This study supports decision makers in priotizing different pollutant control measures based on their predicted performance on the water quality improvements in an agriculturally dominated watershed.

• Journal of The Korean Society of Clinical Toxicology
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• v.13 no.2
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• pp.78-86
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• 2015

Purpose: The purpose of this study is to understand what kinds of chemical substances have been used annually and to investigate incidents that occurred due to chemical hazard release and to analyze statistically clinically chemical injury patients who visited one regional emergency medical center in Gumi city with documented references review. Methods: Annual chemical waste emission quantity (Kg/Year) (Cwep) was reproduced using national web site data governed by the Ministry of Environment and 5 years (from 1 .Jan. 2010 to 31. Dec. 2014) of medical records of chemical injury patients who visited our emergency department were reviewed retrospectively. By applying exclusion criteria, 446 patients of 460 patients were selected. Results: Dichloromethane, Toluene, Trichloroethylene, and Xylene were always included within Top 5 of Cweq. Six cases of chemical incidents were reported and in 3 of 6 cases involving Hydrogen fluoride were included during the study period. Male gender and twenties were the most prevalent group. Injury evoking chemicals were Hydrogen fluoride, unknown, complex chemicals (over 2 substances) in sequence. The most frequent site of wounds and injuries was the respiratory tract. Gas among status, intoxication among diagnosis, and discharge among disposition was most numerous in each group. Conclusion: There have been no uniform clinical protocols for chemical wounds and injuries due to various kinds of chemicophysical properties and ignorance of antidotes. Therefore conduct of a multicenter cohort study and experiments for ruling out chemicals according to chemicophysical priority as well as development of antidotes and clinical protocols for chemical injury patients is needed.