• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.545-550
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• 2017

As an alternate technique for water softening, high voltage impulse (HVI) is introduced and verified if it can control the $CaCO_3$ scale formation in industrial water treatment. After HVI was applied to the artificial hard water containing $100{\pm}5mg/L$ $Ca^{2+}$ for 4 hours, the $Ca^{2+}$ concentration and the electrical conductivity were measured. The concentration of $Ca^{2+}$ was reduced from 94.5 to 86.3 mg/L (8.7% reduction) after 4 hour contact of HVI under 5 kV condition. The $Ca^{2+}$ was decreased from 92 to 77.7 mg/L (15.6% reduction) at 8kV and from 90.1 to 75.4 mg/L (16.3% reduction) at 12 kV condition. Both of the contact time and the applied voltage were important parameters affecting the calcium ion reduction. With these results, it was verified that HVI technique could be potential candidate for control of $CaCO_3$ scale formation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.1-9
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• 2005

This study was conducted to investigate the effect of aquatic plant as a botanical air purification on the indoor air pollution by formaldehyde. Three aquatic plants such as Eichhornia crassipes, Cyperus alternifolius, Echinodorus cordifolius, were selected for this study and they were placed in the artificially contaminated chamber under laboratory condition. The results showed that all three plants could remove the formaldehyde from the contaminated air system effectively. Reduction in the formaldehyde levels by Eichhornia crassipes, which is the floating plant, might be associated with the factors of plant and water. Reduction in the formaldehyde levels by Cyperus helferi and Echinodorus cordifolius, which were emergent plant, was due to the complex effect of plant, soil medium and water. In aquatic plant system, dissolution, microbial degradation in rhizosphere, uptake through root and shoot, sorption to soil and shoot, hydrolysis are known as the main mechanisms of water soluble pollutants in the given system. The advantages of indoor air quality control system using aquatic plants can be; 1) various purifying mechanisms than foliage plants, 2) effective for decontamination of water soluble pollutants; 3) easy for maintenance; 4) diverse application potential. Therefore it was suggested from the results that indoor air control system of aquatic plants should be more effective for reduction of indoor air pollutants.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.512-517
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• 2007

The limiting nutrient of eutrophication in freshwater bodies in Korea was examined and the phosphorus concentration standard for sewage treatment effluent was discussed. The weight ratio of N/P in 13 major reservoirs showed the range of 18 to 163, which implies phosphorus is more limited than nitrogen for algal growth. In the correlation analysis phosphorus showed higher correlation with chlorophyll-a concentration than with nitrogen. In the algal bioassay phosphorus spike test enhanced algal growth in all 25 samples of five reservoirs, while nitrogen was found to co-limit only in four samples. It confirms that phosphorus is the only limiting nutrient for eutrophication in Korean reservoirs. As many reservoirs are eutrophic in Korea, phosphorus control is critical for the management of water quality. The phosphorus standard of sewage treatment effluent in Korea was compared with other countries, and it can be concluded that phosphorus standard is too high to be effective in eutrophication control and a lower phosphorus standard is essential for the water quality improvement.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.43-47
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• 2019

In this study, capability of an air slot in a siphon spillway for controlling outflow discharge is investigated through hydraulic experiments. Arc and rectangular shapes of air slot are considered and the open area of air slot can be varied. Complex air-regulated flow occurs inside the the siphon spillway when the air slot is installed on it. The same discharge is measured at the same water level inside the reservoir when the water level rises or falls. Nondimensional discharge through the siphon spillway increases slowly as nondimensional open area of the air slot increases. The hydraulic experiments show that the control of outflow discharge of siphon spillway is possible by controlling the open area of the air slot.

• Geomechanics and Engineering
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• v.17 no.5
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• pp.475-483
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• 2019

Vegetation cover plays a vital role in stabilizing the soil structure, thereby contributing to surface erosion control. Surface vegetation acts as a shelterbelt that controls the flow velocity and reduces the kinetic energy of the water near the soil surface, whereas vegetation roots reinforce the soil via the formation of root-particle interactions that reduce particle detachment. In this study, two vegetation-testing trials were conducted. The first trial was held on cool-season turfgrasses seeded in a biopolymer-treated site soil in an open greenhouse. At the end of the test, the most suitable grass type was suggested for the second vegetation test, which was conducted in an environmental control chamber. In the second test, biopolymers, namely, starch and xanthan gum hydrogels (pure starch, pure xanthan gum, and xanthan gum-starch mixtures), were tested as soil conditioners for improving the water-holding capacity and vegetation growth in sandy soils. The results support the possibility that biopolymer treatments may enhance the survival rate of vegetation under severe drought environments, which could be applicable for soil stabilization in arid and semiarid regions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.10
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• pp.3275-3298
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• 2022

Cloud-based architectures for precision agriculture are domain-specific controlled and require remote access to process and analyze the collected data over third-party cloud computing platforms. Due to the dynamic changes in agricultural parameters and restrictions in terms of accessing cloud platforms, developing a locally controlled and real-time configured architecture is crucial for efficient water irrigation and farmers management in agricultural fields. Thus, we present a new implementation of an independent sensor-enabled architecture using variety of wireless-based sensors to capture soil moisture level, amount of supplied water, and compute the reference evapotranspiration (ETo). Both parameters of soil moisture content and ETo values was then used to manage the amount of irrigated water in a small-scale agriculture field for 356 days. We collected around 34,200 experimental data samples to evaluate the performance of the architecture under different agriculture parameters and conditions, which have significant influence on realizing real-time monitoring of agricultural fields. In a proof of concept, we provide empirical results that show that our architecture performs favorably against the cloud-based architecture, as evaluated on collected experimental data through different statistical performance models. Experimental results demonstrate that the architecture has potential practical application in a many of farming activities, including water irrigation management and agricultural condition control.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.88-92
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• 2006

This study is intended to check the flame temperature to raise in burning grade C heavy fuel oil and emulsion fuel oil in a boiler and to measure the concentration of Dry Shoot(DS) and Soluble Organic Fraction(SOF) after collecting the Particulate Matters (PM). The flames temperature in boiler was measured by burning grade C heavy oil and oil-water emulsion (C heavy oil $70\%\;and\;30\%$ of water) Combustion characteristics of two fuels was also compared by trapping particulate matters (PM) in exhaust gas and measuring the generated quantities of DS and SOF in fuel gas.

• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.71-76
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• 1996

Bio-film module system was applied to the treated leachate water that priorly had been treated with biological nitrification process. The experiments were performed in the laboratory and treated leachate water treatment facility. Experimental results obtained from laboratory conditions and nitrogen removal efficiencies were averaged 90% for 1 hr.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2678-2680
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• 2005

본 연구는 산업현장에서 널리 사용되고 있는 PLC(Programmable Logic Controller)의 정의와 구조에 대해 설명하였다. 또한 기존의 유선형PLC에 IT기술을 접목시킨 네트워크 지향형 콘트롤러의 개념, 원리 및 산업현장 조건에 따라 네트워크시스템 제어방식을 달리 적용하여 최적의 시스템을 구현하는 유, 무선PLC의 적용사례를 연구하여 시스템 제어의 첨단화, 신뢰성, 경제성을 기술하였다.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.191-196
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• 1998

This mini review describes the effects of water activity (${\alpha}_w$) on the kinetics, regio- and enantioselectivities of lipases, and various methods for measuring and controlling ${\alpha}_w$ in lipase catalyzed reaction in organic solvent.