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철과 망간이 동시에 코팅된 반응성 매질을 이용한 용존 Fe(2) 제거
민상윤(Sang Yoon Min),장윤영(Yoon Young Chang),양재규(Jae Kyu Yang) 大韓環境工學會 2011 대한환경공학회지 Vol.33 No.2
본 연구에서는 산화망간과 산화철이 단독 및 복합 코팅된 반응성매질인 망간코팅사(MCS), 철코팅사(ICS) 그리고 철-망 간코팅사(IMCS)를 이용하여 용존 Fe(II)의 산화 및 제거능을 평가하였다. 반응성매질에 KMnO₄와 NaOCl를 추가적인 산화제로 이용하였을 때의 Fe(II) 제거능을 반응용액의 pH, 반응시간, Fe(II) 농도변화에 따라 조사하였다. 반응성매질 및 추가적인 산화제 없이 Fe(II) 용액만을 사용한 경우, pH 5 이하에서는 Fe(II)의 느린 산화에 의해 제거율이 낮았으나 이후에는 빠른 산화 및 침전반응에 의해 제거율이 증가하였다. ICS만을 사용하였을 때 ICS 표면에 의한 Fe(II)의 제거는 극히 제한적인 것으로 나타났다. 망간 산화물이 코팅된 IMCS와 MCS를 사용한 경우 낮은 pH에서도 Fe(II)가 산화망간에 의해 산화되었으며 용액으로부터 효과적으로 제거되는 것으로 나타났다. Fe(II)는 IMCS만 단독으로 사용했을 때와 NaOCl을 산화제로 사용했을 때 제거율에서 큰 차이가 나지 않았다. IMCS와 산화제를 이용하여 Fe(II)을 제거할 경우, 용액의 pH가 증가함에 따라 이들의 산화능이 증가하였고 이로써 전체 제거율의 증가를 가져왔다. Fe(II)의 제거에 관한 반응속도 실험결과 유사-1차 반응 보다는 유사-2차 반응 식으로 더 잘 표현되었으며 KMnO₄를 추가적인 산화제로 이용한 경우 Fe(II)는 14,286 mg/kg·hr의 높은 초기 제거율(h)을 보였다. KMnO₄ 주입 시 반응시간 10분 안에 제거평형에 도달하였고 NaOCl의 경우는 6시간 후에 거의 제거평형에 도달하는 것으로 나타났다. IMCS에 의한 Fe(II)의 최대 제거량 값을 구하기 위해 pH 4에서 Langmuir 등온식에 적용한 결과 1,088 mg/kg의 제거량을 보였다. Evaluation of the removal efficiencies of Fe(II) by reactive sand media coated with manganese (MCS), iron (ICS) and both of iron and manganese (IMCS) was investigated as functions of solution pH ranging from 2 to 9, reaction time and concentration of Fe(II) in a batch reactor using each reactive medium and additional oxidants such as KMnO₄ and NaOCl. When only Fe(II) was present in solution without any reactive medium, removal of Fe(II) was quite low below pH 5 due to a slow oxidation of Fe(II) and/or negligible precipitation but greatly increased above pH 5 due to a rapid oxidation of Fe(II) and subsequent precipitation of oxidized Fe species. ICS showed negligible efficiency on the removal of Fe(II) through adsorption. However, an efficient removal of Fe(II) was observed at low solution pH in the presence of IMCS or MCS through rapid oxidation and subsequent precipitation. Removal efficiency of Fe(II) by IMCS in the presence or absence of NaOCl was quite similar. Removal rate of Fe(II) by IMCS and additional oxidants gradually increased as the solution pH increased. From the kinetic experiments, removal pattern of Fe(II) was better described by pseudo-second-order equation than pseudo-first-order equation. A rapid removal of Fe(II) using IMCS in the presence of KMnO₄ was observed in the first 10 min. The initial removal rate of Fe(II) using KMnO₄ was 14,286 mg/kg·hr. In case of using NaOCl, the removal of Fe(II) occurred rapidly in the first 6 hrs and then reached the near-equilibrium state. Removal of Fe(II) on IMCS was well expressed by Langmuir isotherm and the maximum removal capacity of Fe(II) was calculated as 1,088 mg/kg.
고압나트륨 및 플라즈마 램프 보광이 절화 장미의 품질 및 수량에 미치는 영향
이민정(Min Jung Lee),서효숙(Hyo Sook Seo),민상윤(Sang Yoon Min),이진희(Jinhee Lee),박수현(Suhyun Park),전정빈(Jeong Bin Jeon),김지선(Jiseon Kim),오욱(Wook Oh) 한국원예학회 2021 원예과학기술지 Vol.39 No.1
Used as supplemental lighting (SL) in protected flower growing systems, newly developed sulfur plasma lamps (PLS) may confer benefits in terms of growth, yield, and quality. This study compared the effects of SL with PLS versus conventional high-pressure sodium lamps (HPS) on the growth characteristics, yield, and quality of cut roses cultivated in winter. Between October 10, 2016 and March 23, 2017, standard cut rose (Rosa hybrida) cultivars ‘Aqua’ and ‘Brut’ were grown under PLS and HPS with a photosynthetic photon flux density (PPFD) of 120 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> for 14 hours (between 17:00 and 07:00). Rose plants were cultivated in a plastic greenhouse in Gyeongsan, Gyeongsangbuk-do. A control condition used HPS with PPFD at 10 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> to offset the effect of the photoperiod. Cut flowers were harvested twice a week from December to March, and their growth and flowering characteristics, yield and quality of cut flowers were measured at each harvest. PLS had more blue (B) light and less red (R) light and near-infrared light than HPS; green and far-red light (FR) levels were similar. Plants under SL with PLS therefore received a higher B:R ratio and lower R:FR ratio than those under HPS. SL with PLS and HPS improved almost all of the characteristics of ‘Aqua’ and ‘Brut’ compared with the control. In particular, SL with PLS in ‘Aqua’ increased cut flower length, fresh and dry weights, vase life, and the number of higher grade products than SL with HPS. These differences could be associated with the relatively low R:FR ratio of PLS, which may have increased stem length and leaf area, thus increasing photosynthesis and resulting in higher yield and quality of cut flowers, as well as a shorter crop period. Likewise, the relatively high B:R ratio of PLS may have promoted gas exchange through stomatal opening and increased photosynthesis, resulting in higher yield and quality. However, the effect of light source for SL on morphological characteristics such as leaf area and stem length may be somewhat cultivar-dependent because the effect of SL with PLS in ‘Brut’ was smaller than that in ‘Aqua’.
쉴드 TBM 터널에 적용 가능한 리스크 관리: II. 리스크 분석 방법
현기창,민상윤,문준배,정경환,이인모,Hyun, Ki-Chang,Min, Sang-Yoon,Moon, Joon-Bai,Jeong, Gyeong-Hwan,Lee, In-Mo 한국터널지하공간학회 2012 한국터널지하공간학회논문집 Vol.14 No.6
본 논문에서는 쉴드 TBM 터널에서 적용 가능한 리스크 분석 방법을 연구하였다. FTA 방법을 통해 리스크 아이템과 각각의 발생확률을 확인하고 AHP 방법을 통해 각각의 리스크 아이템의 영향도를 구하였다. 마지막으로 각각의 리스크 아이템의 리스크 레벨을 평가할 수 있었다. 개발된 방법을 EPB 쉴드 터널이 사용된 서울 지하철 현장에 적용하여 리스크 분석 결과가 현장 데이터에 부합하는 합리적 결과임을 검증하였다. In this paper, a risk analysis methodology applicable to shield TBM tunnels was studied. Fault Tree Analysis (FTA) was utilized to identify all risk items and to calculate the probability of failure of each item and Analytic Hierarchy Process (AHP) was used to obtain the impact of each risk item. Finally, a risk level of each risk item can be assessed. Developed methodology is applied to a Seoul subway site in which EPB shield tunnel method was utilized and it was found that risk analysis results matched reasonably well with field data.
쉴드 TBM 터널에 적용 가능한 리스크 관리: I. 리스크 요인 분석
현기창,민상윤,문준배,정경환,이인모,Hyun, Ki-Chang,Min, Sang-Yoon,Moon, Joon-Bai,Jeong, Gyeong-Hwan,Lee, In-Mo 한국터널지하공간학회 2012 한국터널지하공간학회논문집 Vol.14 No.6
일반적으로 리스크 관리는 리스크 확인, 리스크 분석, 리스크 평가, 리스크 대책, 리스크 재평가를 포함하는 일련의 과정으로 구성된다. 본 논문에서는 쉴드 TBM 터널에서 발생 가능한 리스크 요인들을 여러 문헌 자료와 워크샵을 바탕으로 조사하였다. 리스크 요인들은 지질 요인, 설계 요인, 시공 관리 요인으로 구분되었다. Fault Tree도는 리스크들을 커터, 기계 구속, 배토(굴진), 세그먼트과 관련된 4그룹으로 분류하여 작성되었다. FT도로부터 12가지 리스크 아이템을 확인하고 각각의 발생확률을 구하였다. In general, risk management consists of a series of processes or steps including risk identification, risk analysis, risk evaluation, risk mitigation measures, and risk re-evaluation. In this paper, potential risk factors that occur in shield TBM tunnels were investigated based on many previous case studies and questionaries to tunnel experts. The risk factors were classified as geological, design or construction management features. Fault Tree was set up by dividing all feasible risks into four groups that associated with: cutter; machine confinement; mucking (driving) and segments. From the Fault Tree Analysis (FTA), 12 risk items were identified and the probability of failure of each chosen risk item was obtained.