• 한국습지학회지
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• 제13권2호
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• pp.199-208
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• 2011

세계적으로 물의 부족, 온실가스 배출증가, 에너지 소비 증가 등으로 인하여 지구가 위협받고 있다. 기존의 도시 계획 및 개발 과정에서 산림, 하천 등 자연 생태계가 파괴되어 왔으며 이는 불투수면의 증가를 초래하였다. 불투수면의 증가로 인하여 자연적인 물순환 체계가 파괴됨에 따라 도시내 물의 저류, 침투, 증발 등이 감소되고 있으며, 강우시 불투수면에서 발생하는 비점오염원이 하천 및 호소로 직접 유입되어 수계에 악영향을 끼치고 있는 실정이다. 본 연구에서는 강우시 불투수면에서 발생하는 비점오염물질을 저감하고 불투수면의 증가로 인한 도시지역의 온도증가, 열섬현상 등을 해결하는 소규모 HSSF 인공습지 기술을 개발하고자 한다. HSSF 인공습지는 표면에 물이 존재하지 않고 유체의 흐름이 표면 아래 수평으로 흐르는 습지이며 침전, 여과, 흡착, 식생에 의한 흡수 등의 기작을 포함한다. 이러한 HSSF 인공습지를 도시지역의 협소한 공간에도 적용이 가능한 소규모 형태로 개발하고자 pilot-scale test를 실시하였으며, 이러한 연구결과는 향후 국내 도시 열섬현상 저감 및 자연적 물순환 복원을 위한 시설 개발에 기초자료로 활용 될 것이다.

• Membrane and Water Treatment
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• 제8권4호
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• pp.355-367
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• 2017

In India, the current operation of condenser cooling system & effluent disposal system in existing power plants aims to reduce drawal of seawater and to achieve Zero Liquid Discharge to meet the demands of statutory requirements, water scarcity and ecological system. Particularly in the Steam-Electric power plants, condenser cooling system adopts Once through cooling (OTC) system which requires more drawal of seawater and effluent disposal system adopts sea outfall system which discharges hot water into sea. This paper presents an overview of closed-loop technology for condenser cooling system and to achieve Zero Liquid Discharge plant in Steam-Electric power plants making it lesser drawal of seawater and complete elimination of hot water discharges into sea. The closed-loop technology for condenser cooling system reduces the drawal of seawater by 92% and Zero Liquid Discharge plant eliminates the hot water discharges into sea by 100%. Further, the proposed modification generates revenue out of selling potable water and ZLD free flowing solids at INR 81,97,20,000 per annum (considering INR 60/Cu.m, 330 days/year and 90% availability) and INR 23,760 per annum (considering INR 100/Ton, 330 days/year and 90% availability) respectively. This proposed modification costs INR 870,00,00,000 with payback period of less than 11 years. The conventional technology can be replaced with this proposed technique in the existing and upcoming power plants.

• 한국수처리학회지
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• 제26권6호
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• pp.109-115
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• 2018

This study was conducted to solve the water shortage problem by reclaiming urine from homes or public places and using it as cleaning water for toilets. The process used in this experiment is a chemical oxidation process combining ozone, hydrogen peroxide, and UV. We set the key substance that is to be removed as chromaticity and conducted the experiment to remove it. If the quantity or concentration of injected ozone, UV, and hydrogen peroxide is insufficient, then the chromaticity will initially increase due to low oxidizing power, and will later decrease. In addition, the efficiency of removing chromaticity appeared to be higher, depending on the quantity of ozone injected, for medium concentrated urine than highly concentrated urine. However, the absolute quantity of removed chromaticity was about 68% higher for highly concentrated urine, when 16 g/hr of ozone was injected. The higher the pH level, the reaction time and efficiency of removing chromaticity were higher, and in normal conditions, in reference to a pH of 8.55, there was a 6% difference in efficiency between a pH level of 5.05 and a pH level of 10.12. Finally, when processing urine through an ozone-only process, COD decreased steadily over time, but DOC did not decrease. This is because ozone reacts selectively with organic matter.

• Journal of Plant Biotechnology
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• 제50권
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• pp.127-136
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• 2023

Water scarcity decreases the rate of photosynthesis and, consequently, the yield of banana plants (Musa spp). In this study, transcriptome analysis was performed to identify photosynthesis-related genes in banana plants and determine their expression profiles under water stress conditions. Banana plantlets were in vitro cultured on Murashige and Skoog agar medium with and without 10% polyethylene glycol and marked as BP10 and BK. Chlorophyll contents in the plant shoots were determined spectrophotometrically. Two cDNA libraries generated from BK and BP10 plantlets, respectively, were used as the reference for transcriptome data. Gene ontology (GO) enrichment analysis was performed using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) and visualized using the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway prediction. Morphological observations indicated that water deficiency caused chlorosis and reduced the shoot chlorophyll content of banana plantlets. GO enrichment identified 52 photosynthesis-related genes that were affected by water stress. KEGG visualization revealed the pathways related to the 52 photosynthesisr-elated genes and their allocations in four GO terms. Four, 12, 15, and 21 genes were related to chlorophyll biosynthesis, the Calvin cycle, the photosynthetic electron transfer chain, and the light-harvesting complex, respectively. Differentially expressed gene (DEG) analysis using DESeq revealed that 45 genes were down-regulated, whereas seven genes were up-regulated. Four of the down-regulated genes were responsible for chlorophyll biosynthesis and appeared to cause the decrease in the banana leaf chlorophyll content. Among the annotated DEGs, MaPNDO, MaPSAL, and MaFEDA were selected and validated using quantitative real-time PCR.

• Geomechanics and Engineering
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• 제15권2호
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• pp.729-738
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• 2018

Soft clay soils due to their various geotechnical problems, stabilized with different additives. Traditional additives such as cement and lime will not able to increase the soil strength properties significantly. So, it seems necessary to use new additives for increasing strength parameters of soft clay soils significantly. Among the new additives, epoxy resins have excellent physical and mechanical properties, low shrinkage, excellent resistance to chemicals and corrosive materials, etc. So, in this research, epoxy resin used for stabilization of soft clay soils. For comprehensive study, three clay soil samples with different PI and various clay mineral types were studied. A series of uniaxial tests, SEM and XRD analysis conducted on the samples. The results show that using epoxy resin increases the strength parameters such as UCS, elastic modulus and material toughness about 100 to 500 times which the increase was dependent on the type of clay minerals type in the soil. Also, In addition to water conservation, the best efficiency in the weakest and most sensitive soils is the prominent results of stabilization by epoxy resin which can be used in different climatic zones, especially in hot and dry and equatorial climate which will be faced with water scarcity.

• 한국인터넷방송통신학회논문지
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• 제11권4호
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• pp.195-201
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• 2011

주파수 자원을 효율적으로 이용하기 위한 기술인 인지무선통신(CR : Cognitive radio) 기술은 주파수 자원난을 해결하기 위하여 연구되고 있다. CR은 1차 사용자에 할당된 주파수를 2차 사용자가 이용할 수 있도록 한다. 그러나 무선채널에서는 페이딩과 음영지역의 영향으로 스펙트럼 센싱에 있어서 절충안이 필요해진다. 또한, 다양한 CR 시스템을 검출하고 구분하기 위해서 새로운 센싱 알고리즘이 필요하다. 그러므로 본 논문에서는 워터마킹 기술을 이용한 스펙트럼 센싱 알고리즘을 제안하여, Kasami-sequence와 M-sequence를 워터마킹 시퀀스로 이용했을 경우의 검출 성능을 비교한다.

• 한국물환경학회지
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• 제33권4호
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• pp.403-408
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• 2017

In these days, wastewater reclamation and seawater desalination play essential role in addressing the challenge of worldwide water scarcity. Particularly, reverse osmosis (RO) for seawater desalination process is commonly used due to less energy consumption than conventional thermodynamic systems. However, membrane fouling and electrical energy consumption during operation of RO system for seawater desalination haver continued to be a obstruction to its application. In this study, therefore, wastewater secondary effluent is used for osmotic dilution of seawater. Firstly, fouling behaviour of RO by simulating wastewater effluent in osmotic dilution process was measured and we calculated energy consumption of overall desalination process by theoretical equations and commercial program. Our results reveal that RO membrane fouling can be efficiently controlled by pre-treatment systems such as nano filtration (NF) or forward osmosis (FO) process. Especially FO system for osmotic dilution process is a non-pressurized membrane system and, therefore, the operating energy consumption of overall desalination system was the lowest. Moreover, fouling layer on FO membrane is comparatively weak and reversible enough to be disrupted by physical cleaning. Thus, RO system with low salinity feed water through FO process is possible as a less energy consuming desalination system with efficient membrane fouling control.

• 멤브레인
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• 제31권4호
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• pp.241-252
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• 2021

급격한 산업화와 인구수 증가로 인한 환경 수질 오염이 발생하고 있다. 더불어 날씨 패턴의 변화로 인해 빗물이 부족해지자, 폐수를 깨끗한 물로 재활용하기 위한 요구가 나날이 늘어나고 있다. 색변화를 이용한 수중 속 중금속 검출은 아주 간단하고 효과적인 기술이다. 본 논문에는 멤브레인을 이용한 수은 이온 색검출에 대해 자세하게 논의되어 있다. 셀룰로스, 폴리카프로락톤, 키토산, 폴리설폰 등의 멤브레인이 금속 이온 검출을 지지체로서 사용되었다. 지지체로서 사용된 멤브레인들은 나노 섬유를 기반으로 하며 표면적이 크며, 중금속 검출의 활성 부위로 사용하기에 탁월하다. 나노 섬유를 기반으로 한 재료는 에너지, 환경, 그리고 바이오메디컬 연구에서 다양하게 응용될 수 있다. 나노 섬유로 이루어진 멤브레인들은 폴리머에 있는 적용기를 많이 받아들일 수 있으며, 표면적이 넓고 다공성이라는 장점이 있다. 이로 인해 멤브레인의 표면 구조를 변화시키거나 리간드를 섬유 표면에 부착해 나노 입자 결합을 더 쉽게 해준다.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.5661-5668
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• 2012

물 부족 시대에 양변기 절수는 물을 절약하는데 가장 효과적인 방법 중 하나이다. 본 연구에서는 고절수형 양변기 개발을 위한 이상유동 해석을 위해 VOF 기법을 이용하였다. VOF를 이용한 전체 모델의 해석은 많은 시간이 요구되므로 전체모델의 일부분만 고려하는 부분모델도 해석시간 단축을 위해 사용하였다. 유량배분 해석을 위해 4개의 서로 다른 림 모델을 고려하였는데 림 홀의 위치나 개수보다는 림 홀의 크기가 유량배분을 효과적으로 달성하기 위한 인자임이 본 연구를 통해 밝혀졌다. 또한, 전체모델 해석을 통해 사이펀 현상에 따른 이상유동의 속도 및 압력도 분석하였다. 따라서 본 연구는 고절수형 양변기 모델 개발을 위한 다양한 기초 데이터를 제공한다.

• Geomechanics and Engineering
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• 제4권4호
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• pp.281-294
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• 2012

Filtration using granular media such as quarried sand, anthracite and granular activated carbon is a well-known technique used in both water and wastewater treatment. A relatively new pre-filtration method called pebble matrix filtration (PMF) technology has been proved effective in treating high turbidity water during heavy rain periods that occur in many parts of the world. Sand and pebbles are the principal filter media used in PMF laboratory and pilot field trials conducted in the UK, Papua New Guinea and Serbia. However during first full-scale trials at a water treatment plant in Sri Lanka in 2008, problems were encountered in sourcing the required uniform size and shape of pebbles due to cost, scarcity and Government regulations on pebble dredging. As an alternative to pebbles, hand-made clay pebbles (balls) were fired in a kiln and their performance evaluated for the sustainability of the PMF system. These clay balls within a filter bed are subjected to stresses due to self-weight and overburden, therefore, it is important that clay balls should be able to withstand these stresses in water saturated conditions. In this paper, experimentally determined physical properties including compression failure load (Uniaxial Compressive Strength) and tensile strength at failure (theoretical) of hand-made clay balls are described. Hand-made clay balls fired between the kiln temperatures of $875^{\circ}C$ to $960^{\circ}C$ gave failure loads of between 3.0 kN and 7.1 kN. In another test when clay balls were fired to $1250^{\circ}C$ the failure load was 35.0 kN compared to natural Scottish cobbles with an average failure load of 29.5 kN. The uniaxial compressive strength of clay balls obtained by experiment has been presented in terms of the tensile yield stress of clay balls. Based on the effective stress principle in soil mechanics, a method for the estimation of maximum theoretical load on clay balls used as filter media is proposed and compared with experimental failure loads.