The spectrum of this study was research on the closed hydroponic cultivation of netted melons (Cucumis melo L.) using coir substrate, analyzing the impact of this cultivation method on melon yield, fruit quality, and the efficiency of water and nutrient usage. The experimental results showed that the average fruit weight of the melons grown in a closed system was 71.4 g higher than that of the open system, and the fruit width was on average 0.2 cm larger, showing a statistically significant difference. However, there was no difference in the average sugar content of the fruit flesh and height. Although there is no substantial commercial difference, it is conjectured that the change in the macronutrients ratio in the irrigation has played a role in the statistically significant increase in fruit weight, which is attributed to changes in the crops' nutrient uptake concentrations. This necessitates further research for a more comprehensive understanding. In terms of the productivity of irrigation required to produce the fruit, applying the closed system resulted in an increase of 7.6 kg/ton compared to the open system, saving 31.6% of water resources. Additionally, in terms of nutrients, cultivating in a closed system allowed for savings of approximately 59, 25, 55, 83, 76, and 87% of N, P, K, Ca, Mg, and S, respectively, throughout the entire cultivation period. As the drainage was reused, the ratios of NO3 - and Ca2+ increased up to a maximum of 9.6 and 9.1%, respectively, while the ratios of other ions gradually decreased. In summary, these results suggest that closed hydroponic cultivation can effectively optimize the use of water and fertilizer while maintaining excellent fruit quality in melon cultivation.

With a rapid expansion in electric vehicles, a huge amount of the spent Li-ion batteries (LIBs) could be discharged in near future. And thus, the proper handling of the spent LIBs is essential to sustainable development in the industry of electrical vehicles. Among various approaches such as pyrometallurgy, hydrometallurgy, and direct recycling, the hydrometallurgical manner has gained interest in recycling the spent LIBs due to its high effectiveness in recycling raw materials (e.g., lithium, nickel, cobalt, and manganese). However, the hydrometallurgical process not only requires the use of large amounts of acids and water resources but also produces toxic gases and wastewater leading to environmental and economic problems, considering potential economic and environmental problems. Thus, this review aims to provide an overview of conventional and state-of-the-art hydrometallurgical processes to recover valuable metals from spent LIBs. First, we briefly introduce the basic principle and materials of LIBs. Then, we briefly introduce the operations and pros-and cons- of hydrometallurgical processes. Finally, this review proposes future research directions in hydrometallurgy, and its potential opportunities in the fundamental and practical challenges regarding its deployment going forward.

Urban areas in watersheds increase the impervious surface, and agricultural areas deteriorate the water quality of rivers due to the use of fertilizers. As such, anthropogenic land use affects the type, intensity and quantity of land use and is closely related to the amount of substances and nutrients discharged to nearby streams. Riparian vegetation reduce the concentration of pollutants entering the watershed and mitigate the negative impacts of land use on rivers. This study analyzes the data through correlation analysis and regression analysis through point data measured twice a year in spring and autumn in 21 selected damaged tributary rivers within the Han River area, and then uses a structural equation model to determine the area land use. In the negative impact on water quality, the mitigation effect of riparian vegetation was estimated. As a result of the correlation analysis, the correlation between the agricultural area and water quality was stronger than that of the urban area, and the area ratio of riparian vegetation showed a negative correlation with water quality. As a result of the regression analysis, it was found that agricultural areas had a negative effect on water quality in all models, but the results were not statistically significant in the case of urban areas. As a result of the model estimated through the structural equation, BOD, COD, TN, and TP showed a mitigation effect due to the accumulation effect of river water quality through riparian vegetation in agricultural areas, but the effect of riparian vegetation through riparian vegetation was found in urban areas. There was no These results were interpreted as having a fairly low distribution rate in urban areas, and in the case of the study area, there was no impact due to riparian forests due to the form of scattered and distributed settlements rather than high-density urbanized areas. The results of this study were judged to be unreasonable to generalize by analyzing the rivers where most of the agricultural areas are distributed, and a follow-up to establish a structural equation model by expanding the watershed variables in urban areas and encompassing the variables of various factors affecting water quality research is required.

The point-of-use water dispenser systems are widely used because of convenience in handling and demand for high-quality drinking water. The application has been increased recently in the public places such as department stores, universities and the rest areas in express ways. Improvement of water qualities by the dispenser systems was compared with tap water in this study. The tap water is supplied to the dispenser as the influent of the dispenser system. The twelve dispensers in the public places were used. The five dispensers used reverse osmosis as the main filter and other dispensers used various filters such as ultrafiltration, nanofiltration, and alumina filter. The water quality indicators for sanitation safety, i.e., turbidity and total coliforms, were evaluated. Other water qualities such as pH, residual chlorine, heterotrophic plate count (HPC), and total cell counts were also analyzed. By the point-of-use water dispenser, the turbidity, residual chlorine and pH were decreased and the HPC and total cell counts were increased. The t-test results revealed that the HPC of the tap waters were not significantly different from the treated waters but the total cell counts of the two groups were significantly different. The low pH of the RO filter treatment was also significantly different from the tap waters. This study will contribute to understand the role of the point-of-use water dispenser in improving water quality and to identify key water quality for the proper maintenance of the dispenser systems.

Smart farm is a breakthrough technology that can maximize crop productivity and economy through efficient utilization of space regardless of external environmental factors. This study was conducted to investigate the optimal growth and physiological conditions of Chinese matrimony vine (Lycium chinense) with LED light sources in a smart farm. The light source was composed of red+blue and red+blue+white mixed light using a LED system. In the red+blue mixed light, red and blue colored LEDs were mixed at ratios of 1:1, 2:1, 5:1, and 10:1, with duty ratios varied to 100%, 99%, and 97%. The experimental results showed that the photosynthetic rate according to the types of light sources did not show statistically significant differences. Meanwhile, the photosynthetic rate according to the mixed ratio of the red and the blue light was highest with the red light and blue LED ratio of 1:1 while the water use efficiency was highest with the red and blue LED ratio of 2:1. The photosynthetic rate according to duty ratio was highest with the duty ratio of 99% under the mixed light condition of red+blue+white whereas the water use efficiency was highest with the duty ratio of 97% under the mixed light of red+blue LED. The results indicate that the light source and light quality for the optimal growth of Lycium chinense in the smart farm using the LED system are the mixed light of red+blue (1:1) and the duty ratio of 97%.

본 연구는 금강 권역을 대상으로 일반최소자승법(OLS)과 공간지리 가중회귀모형(GWR)을 적용하여 유역 내 토지이용과 지형적 특성이 BOD, DO, TN, TP을 포함한 수질에 미치는 영향을 알아보고자 하였다. 일반적으로 OLS는 변수 간의 관계가 균일하다는 가정에 기초하고 있으며, 지역적인 변화를 고려하지 않는다는 한계가 있다. 따라서 본 연구에서는 변수 간의 관계가 지역적으로 다르게 나타나는 것을 검증하기 위해 GWR을 이용하여 분석하였다. 종속변수인 총 4 개의 수질 측정 항목 (BOD, DO, TN, TP)과 독립변수인 토지이용 비율 (도시, 농업 및 산림지역) 및 지형 (고도, 평균 경사)에 대하여 OLS와 GWR 모형을 각각 추정하고, 비교하였다. GWR 모형의 R2와 회귀계수 값의 기초 통계량을 분석한 결과, 공간적으로 큰 변동성이 있는 것으로 나타났다. 즉, 토지이용과 지형이 수질에 미치는 영향이 지역에 따라 균일하지 않은 (non-stationarity) 것을 보여준다. 또한 OLS와 GWR 모형의 R2, AICc, Moran’s I 지수를 비교하였을 때, 대부분 GWR 모형이 OLS 모형에 비하여 우수한 것으로 나타났다. 본 연구 결과는 향후 수질 및 유역 관리를 위한 토지이용 계획 수립 등의 정책적 근거로 활용될 수 있다.

본 연구에서는 Hummer`s method를 개선하여 GO를 합성하였다. 전기방사법으로 GO + PAN 나노섬유 복합체 막을 제조하였으며, 표면특성· 인장강도· Flux 및 단백질 제거에 관한 실험을 진행하였다. 또한 GO+계면활성제, rGO로 PAN 나노섬유 복합체 막을 제작하였으며, 물리적 강도 측정 및 염 제거 실험에 활용하였다. GO나 rGO를 함유한 PAN 복합체 분리막의 경우 기계적 특성뿐만 아니라 단백질 및 염 제거에 효과적인 특성을 보여주었다. 이러한 결과를 바탕으로 폐수 속의 유기물질 제거에 효과적인 분리막 연구 기초자료로 활용될 수 있을 것으로 기대된다.

Aging water pipe networks hinder efficient management of important water service indices such as revenue water and leakage ratio due to pipe breakage and malfunctioning of pipe appurtenance. In order to control leakage in water pipe networks, various methods such as the minimum night flow analysis and sound waves method have been used. However, the accuracy and efficiency of detecting water leak by these methods need to be improved due to the increase of water consumption at night. In this study the Principal Component Analysis (PCA) technique was applied to the night water flow data of 426 days collected from a water distribution system in the interval of one hour. Based on the PCA technique, computational algorithms were developed to narrow the time windows for efficient execution of leak detection job. The algorithms were programmed on computer using the MATLAB. The presented techniques are expected to contribute to the efficient management of water pipe networks by providing more effective time windows for the detection of the anomaly of pipe network such as leak or abnormal demand.

The objectives of this study were twofold: to analyze seasonal variation in nutrients and sestonic chlorophyll (CHL-a) in Asian lotic ecosystems, which are influenced by seasonal monsoon rains, and to evaluate multi-trophic level ecological stream health (ESH) in relation to stream morphology, land-use patterns, and water chemistry. We conducted physical, chemical, and biological surveys at 72 national streams and rivers, and at 65 reference streams. Water chemistry data indicated that ambient nutrient (N, P) levels were closely associated with land-use patterns and stream elevation, and that these, in turn, influenced both community structures of fish and stream health in general. In the watershed, total phosphorus (TP) was a key determinant of sestonic CHL-a, and the mass ratio TN:TP was determined by phosphorus (R2 = 0.63, P < 0.01) rather than nitrogen (R2 = 0.01, P > 0.05). Proportions of tolerant and omnivorous fish increased with nutrient enrichment and organic matter pollution, while proportions of sensitive and insectivorous fish decreased. The neural network modeling of a self-organizing map (SOM) suggested that clustering of trained SOM units reflected stream morphology, land-use patterns, and water chemistry, which influenced community structures and tolerances of top trophic level fish species in the ecosystem. Lotic ecosystem health, based on a multi-metric approach (MF-IBI model), was clearly demonstrated by a multivariate analysis (PCA); important factors were watershed characteristics (land-use patterns), nutrient levels (N, P), organic matter (BOD, COD) regimes, and biological components (trophic and tolerance guilds).

본 연구는 홍수기 유량측정의 어려움을 극복하고자 물 과 비접촉식으로 유속을 측정하여 유량을 산정하는 전 자파표면유속계(microwave water surface current meter, MWSCM)의 성능개선 제품인 범용 MWSCM에 대하여 소개하고자 하였다. 기존에 사용 중인 MWSCM은 홍수 용으로써 연중 활용도가 낮아 이것의 이용성을 높이고 자 성능을 개선하였다. 유속측정 범위를 확장하여 평∙ 갈수기에도 하천 유량측정이 가능하게 하였다. 즉 기존 홍수용 MWSCM의 유속측정 범위가 0.5~10.0 m s-1이 었던 반면, 금번에 개발된 범용 MWSCM은 0.03~20.0 m s-1로 홍수기 및 평수기 측정이 가능하도록 성능을 개선하였다. 이를 위해서 사용주파수의 변경(10 GHz → 24 GHz), 안테나 및 송수신부 회로가 새롭게 설계 제작 되었다. 이와 더불어 기존 홍수용 MWSCM 사용자들의 개선요구사항-기기 경량화, 유속 안정화, 자체점검기능, 저전력, 방수 및 방습-을 파악하여 반영함으로써 현장에 서 유량을 측정하기에 용이한 기기로 개발하였다.

본 연구는 영산강수계 13개 소하천 지점에서 2011년 1월부터 2011년 12월까지 측정된 수질자료와 토지이용 자료를 이용하여 토지이용특성에 따른 수질변화를 분석 하였다. 또한 수질항목간 상관성 분석, 수질항목과 토지이 용 점유율에 따른 상관성 분석을 실시하였다. 영산강수계 13개 소하천 중 BOD, COD, TOC, T-N, T-P의 농도가 가 장 높은 지점은 비교적 농경지 면적이 큰 Y11 지점으로 나타났고 상대적으로 농경지 면적보다 임야의 면적이 큰 Y13 지점에서 수질농도가 비교적 낮게 관측되었다. 또한 수질항목간 상관분석 결과 T-N과 SS를 제외한 나머지 모든 항목에서 비교적 높은 양의 상관관계를 나타내었 다. 한편, 토지이용 점유율에 따른 수질항목간 상관분석 결과 논과 밭 면적이 클수록 양의 상관관계를 나타냈고 특히 밭 면적이 클수록 강한 양의 상관관계를 보였다. 이 러한 이유는 논과 밭에 작물생육에 필요한 유기질 비료, 질산질 비료, 인산질 비료가 시용되고 이들이 강우시 토 사와 함께 인근 하천에 아무런 여과 없이 유입되기 때문 인 것으로 판단된다. 이와 다르게 수질항목과 임야와는 강한 음의 상관관계를 보였는데, 이는 이 지역의 경우 논 과 밭이 수질에 악영향을 미치지만 임야의 경우 수질에 긍정적인 영향을 미친다는 것을 의미한다. 따라서, 효율 적 수질관리를 위해서는 논과 밭을 우선적으로 관리해야 될 것으로 판단된다. 본 연구의 결과는 1년간의 수질자료 를 활용하여 수질항목과 토지이용 점유율에 따른 상관성 분석을 통하여 도출한 결과이므로 좀더 신뢰성 있는 수질특성을 파악하기 이해서는 장기간의 자료, 각 하천의 오염원 조사, 오염물질별 배출특성 및 배출구조 등의 연 구가 추가적으로 수행되어야 할 것으로 판단된다.

본 조사에서 확인된 관속식물상은 98과 310속 402종 52 변종 7품종 1아종 462종류로 확인되었다. 한반도 고유종은 국립생물자원관(2011)이 지정한 한반도고유종은 눈주목, 외대으아리 및 할미밀망 등 총 10종류가 확인되었다. 식물 구계학적 식물종은 Ⅴ등급 종은 목련과 왕벚나무로 2종, Ⅳ등급종은 산복사, 측백나무 및 꽃창포 등 3종, Ⅲ등급종 은 단풍나무, 탱자나무 및 노각나무 등 3종, Ⅱ등급 종은 석창포, 주목 및 개고사리 등 3종 그리고 Ⅰ등급 종은 이팝 나무, 회양목 및 거지덩굴 등 8종이 확인되었다. 전주지역 소류지 7곳에서 부유식물은 개구리밥과 좀개구리밥으로 2 분류군, 부엽식물은 마름, 애기마름 및 가는가래 등 6분류 군, 침수식물은 말즘과 물수세미로 2분류군 그리고 정수식 물은 고마리, 왕버들 및 논냉이 등 총 52분류군이 확인되었 다. 귀화식물종은 총 45종류로 국화과가 노랑코스모스, 미 국가막사리, 실망초 및 개망초 등 16종으로 가장 많았고, 다음은 벼과로 메귀리, 큰김의털 및 들묵새 등 7종이, 메꽃 과 4종, 현삼과 3종, 마디풀과, 명아주과, 십자화과, 콩과 및 바늘꽃과는 각 2종 그리고 자리공과, 석죽과, 비름과, 대극과 및 소태나무과 등은 각 1종씩 확인되었다. 환경부 생태계교란식물은 돼지풀, 털물참새피와 물참새피 3종류가 출현하였다. 수질은 COD 기준으로 10이 초과되는 소류지 는 구주제가 16.23, 성곡제 14.59, 황학제 13.79 및 오송제 10.66으로 매우 나쁜 상태를 보였으며, 10이하인 소류지는 지사제 9.48과 서은제 8.65로 나쁜 상태이며, 학소제만 4.74 로 보통상태였다. 소류지 생태공원 이용실태 응답자의 50% 이상이 주 2회 이하로 방문하는 것으로 응답하였으며 생태 공원을 이용함에 있어 가장 큰 이점이 약 50%의 응답자가 스트레스 해소 및 생활 활력의 증가를 꼽았다. 탐방객 중 한 부류는 위락, 편의시설이 잘 구비된 곳보다는 불편하더 라도 한적한 곳을 찾고 싶다는 응답자가 50%를 넘었다.

Water scarcity around the globe and climate change challenges has forced the researchers to develop alternative production systems with higher water use efficiency. Direct seeded rice is the emerging water saving rice production system having higher water use efficiency. Field experiment was conducted to assess the role of different mulch systems in improving water use efficiency and productivity in direct seeded and transplanted rice. Three different rice production systems viz., transplanted rice with continuous flooding, two weeks continuous flooding after transplanting and direct seeding with supplemental irrigation only were evaluated under two ground cover systems i.e., plastic and straw mulching with no mulch taken as control. Super Basmati was used as experimental material. Continuously flooded transplanted rice with plastic mulching resulted in higher paddy yield (4.04 t ha- 1 ); while performance of no mulch direct seeding remained poor in this regard. Two weeks flooded transplanted rice with plastic mulching followed continuous flooding in paddy yield (3.94 t ha- 1 ). Continuously flooded transplanted rice with plastic mulching observed substantial improvement in yield related attributes such as panicle length, number of grains per panicle and 1000 grain weight. Plastic mulching improved the productivity and water use efficiency of transplanted as well as direct seeded rice. Higher water use efficiency was observed in direct seeded rice with plastic mulching as it was grown on supplemental irrigations. In crux productivity and water use efficiency of transplanted and especially direct seeded rice can be improved by using plastic film as mulch in current scenarios of water shortage. Key Words: mulching, rice production systems, water use efficiency, productivity