• 한국건축시공학회지
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• 제14권3호
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• pp.237-243
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• 2014

지구온난화 현상으로 인해 환경 문제가 심각하며, 또한, 시멘트의 원료인 석회석과 골재의 무분별한 채취로 인한 환경파괴와 자원고갈의 심각성이 강조되고 있는 상황에서 문제점을 줄이려는 노력이 지속되고 있는 실정이다. 따라서, 본 연구에서는 천연골재 대체재인 폐자기를 혼합하여 적용시켰다. 또한, 시멘트 대체재로써 마그네시아 인산염 복합체와 플라이애시를 혼입하여 그에 따른 인조석재의 특성을 알아보고자 한다. 실험결과, 폐유리 혼합비율 60% 및 폐자기 혼합비율 70%가 인조석재의 전반적인 실험에서 가장 우수한 것으로 판단되며, 인조석재의 기초적인 자료로 활용할 수 있을 것으로 기대된다.

• 한국토양비료학회지
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• 제9권2호
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• pp.71-76
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• 1976

1. 개량제(改良劑) 시용(施用)에 의(依)한 상엽수량(桑葉收量)의 증수율(增收率)은 표준구(標準區)에 비(比)하여 20~80%이었으며 개량제(改良劑) 처리간(處理間)의 효과(効果)는 고토질석회(苦土質石灰)>퇴비(堆肥)>용성인비(溶成燐肥)>녹비재배(綠肥栽培) 및 환원(還元)>맥간구(麥稈區)의 순위(順位)이었다. 2. 상엽수량(桑葉收量)과 가장 상관도(相關圖)가 높은 생태적요소(生態的要素)는 근중(根重)과 근권체적(根圈體積)이며 그다음으로 지조장(枝條長)과 지조수(枝條數)이었다. 또한 토양(土壌) 및 상엽중(桑葉中)의 Ca과 Mg함량(含量)과 상엽수량(桑葉收量)과는 높은 상관(相關)을 보였다. 3. 지조선단(枝條先端)의 고사현상(枯死現象)은 엽중(葉中) $K_2O$와 MgO함량(含量)의 불균형(不均衡)의 영향(影響)으로부터 오며 상엽중(桑葉中) $K_2O/MgO$의 비(比)가 6.0 또는 그이상(以上)되어야 고손율(枯損率)을 최소(最少)로 할 수 있었다. 4. 토지상전조성(土地桑田造成)을 위(爲)하여는 유기물외(有機物外)에 고토(苦土)를 포함(包含)한 석회질비료(石灰質肥料) 시용(施用)이 필수적(必須的)이나 이들만의 시용(施用)은 고손율(枯損率)을 증가(增加)시키므로 상대적(相對的)으로 가리(加里)의 증시(增施)가 병행(併行)되어야 함을 알았다.

• 한국환경농학회지
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• 제42권1호
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• pp.52-62
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• 2023

This study focused on determining the specific causes and prevention methods of mass fish deaths occurred in five reservoirs (Gagugi, Neupgokgi, Danggokgi, Sagokji, and Hangokji) in Andong-si. For this purpose, a survey of agricultural land and livestock in the upper part of the reservoirs and analysis of water quality in the reservoir irrespective of whether it rains or not were conducted. We attempted to examine the changes in dissolved oxygen (DO) in the surface and bottom layers of reservoirs and changes in DO depending on the amount of livestock compost and time. Based on the above investigations, treatment plans were established to efficiently control the inflow of contaminated water into reservoirs. The rainfall and farmland areas in the upper part of the reservoir were investigated using Google and aviation data provided by the Ministry of Land, Infrastructure, and Transport. The current status of livestock farms distributed around the reservoirs was also examined because compost from these farms can flow into the reservoir when it rains. Various water quality parameters, such as phosphate phosphorus (PO₄-P) and ammonium nitrogen (NH₃-N), were analyzed and compared for each reservoir during the rainy season. Changes in the DO concentration and electrical conductivity (EC) were also observed at the inlet of the reservoir during raining using an automated instrument. In addition, DO was measured until the concentration reached 0 ppm in 10 min by adding livestock compost at various concentrations (0.05%, 0.1%, 0.3%, and 0.5% by wt.), where the concentration of the livestock compost represents the relative weight of rainwater. The DO concentration in the surface layer of reservoirs was 3.7 to 5.3 ppm, which is sufficient for fish survival. However, the fish could not survive at the bottom layer with DO concentration of 0.0-2.1 ppm. When the livestock compost was 0.3%, DO required 10-19 h to reach 0 ppm. Considering these results, it was confirmed that the DO in the bottom layer of the reservoir could easily change to an anaerobic state within 24 h when the livestock compost in the rainwater exceeds 0.3%. The results show that the direct cause of fish mortality is the inflow of excessive livestock compost into reservoirs during the first rainfall in spring. All the surveyed reservoirs had relatively good topographical features for the inflow of compost generated from livestock farms. This keeps the bottom layer of the reservoir free of oxygen. Therefore, to prevent fish death due to insufficient DO in the reservoir, measures should be undertaken to limit the amount of livestock compost flowing into the reservoir within 0.3%, which has been experimentally determined. As a basic countermeasure, minerals such as limestone, dolomite, and magnesia containing calcium and magnesium should be added to the compost of livestock farms around the reservoir. These minerals have excellent pollutant removal capabilities when sprayed onto the compost. In addition, measures should be taken to prevent fish death according to the characteristics of each reservoir.