Continuous Flow Analyzer(CFA)를 이용한 담배 주류연 중 Hydrogen Cyanide(HCN)의 최적 분석방법 구명

나승주,어성재,김도연,복진영,황건중,Na, Seung-Ju,Eo, Sung-Je,Kim, Do-Yeon,Bock, Jin-Young,Hwang, Keon-Joong 한국연초학회 2009 한국연초학회지 Vol.31 No.1

Hydrogen cyanide (HCN) is present in both the particulate and vapor phase of cigarette mainstream smoke. It is one of the 44 harmful substances on Hoffmann's list and is known to be a major ciliatoxic agent in cigarette mainstream smoke. Typically the determination of HCN in cigarette mainstream smoke has been done through colorimetric and electrochemical techniques, such as UV-spectrophotometry (UV), continuous flow analyzer (CFA), ion chromatography (IC) and capillary GC-ECD. In particular, CFA commonly has been using analysis hydrogen cyanide in cigarette smoke and the basic principle is pyridine-pyrazolone reaction. In this study, the more optimized analytical method is suggested isonicotinic acid-pyrazolone reaction method than previous pyridine-pyrazolone reaction method, a commonly used method for the determination of cyanide in water and air, by CFA. Sample collection was optimized by trapping particulate and vapor phase of smoke separately. The optimum NaOH concentration of the trapping solution was shown to be 0.2 M. HCN was stable up to 6 hours in this concentration but only 3 hours in 0.1 M solution. The sensitivity of this method was fairly good and it might be used in analysis of HCN in cigarette mainstream smoke.

XT15(ANCOM)를 활용한 잎담배 에테르 추출물의 최적 분석방법 구명(AOCS Method)

나승주,이정래,하아랑,김석재,서정규,Na, Seung-Ju,Lee, Jung-Lae,Ha, Ah-Rang,Kim, Suk-Jae,Seo, Jung-Kyu 한국연초학회 2010 한국연초학회지 Vol.32 No.2

The ether extract(EE) of leaf tobacco contains diverse compounds such as lipid, resinoid, paraffin hydrocarbons and pigments. Although the correlation of EE concentertion with leaf tobacco has not been established clearly, it is known that in some concentration range, EE concentration of leaf tobacco exerts good influence on the quality of tobacco. Recently, The American Oil Chemist's Society introduced new method(Am 5-04; AOCS, 2009) to determine EE concentration by AT15 extractor. This method is based on extraction with organic solvent at relatively high temperature and pressure, which significantly reduces the extraction time and ensures safety. The aim of this study is to optimize analytical condition of AOCS method for analyzing EE concentration of leaf tobacco. When sample pre-drying time and extraction time of XT15 were set to 3 hour and 30 minute and 30 minute respectively, EE concentration obtained from AOAC method. Statistical analysis(T-test) showed that there is no difference(P>0.05) between EE concentrations from two methods.

GCP로 개량된 복합지반의 관통률에 따른 응력분담비

나승주(Seung-Ju Na),김대현(Daehyeon Kim),이익효(Ik-Hyo Lee),이강일(Kang-Il Lee) 한국지반신소재학회 2017 한국지반신소재학회 논문집 Vol.16 No.2

쇄석다짐말뚝(GCP)은 연약지반의 지지력 증가와 침하량 감소를 실현할 수 있어 연약지반 개량에 활발하게 사용되고 있다. 그리고 GCP 설계에 필요한 응력분담비는 치환율, 상재하중, 깊이, 관통률 등에 따라 달라진다. 그동안 많은 연구자들이 현장•실내 실험, 수치해석 연구를 통해 GCP로 개량된 복합지반의 응력분담비를 제안하였지만 명확하게 제시되지 못한 실정이다. 본 연구에서는 GCP공법의 합리적인 설계법 제안을 위한 기초연구로써, 유한요소해석프로그램인 ABAQUS 6.12-4를 이용하여 GCP로 개량된 복합지반을 모델링하여 치환율과 관통률에 따른 침하량과 응력분담비를 분석하고자 하였다, 그 결과, 최상부 지점을 제외한 다른 지점에서의 응력분담비의 값은 관통률 60%일 때 1.21~5.36, 관통률 80%일 때 1.19∼5.45, 관통률 100%일 때 2.16∼5.60 이었다. 이는 관통률과 치환율이 증가할수록 응력분담비의 값은 크게 증가함을 알 수 있다. Gravel compaction pile (GCP) is widely used as it increases the bearing capacity of soft ground and reduces the consolidation settlement. Stress concentration ratio for design is dependent on the area replacement, surcharge pressure, depth and penetration rate. However, a range of stress concentration ratio obtained through field, laboratory experiments and numerical analysis is large. But since the main objective of the study is to evaluate the stress concentration ratio and settlement for both area replacement ratio and penetration rate through numerical analysis. Numerical analysis using the finite element program ABAQUS 6.12-4 has been performed for the composite ground with GCP. As a result, the stress concentration ratio at the points except for the point of top is in the range of 1.21-5.36, 1.19-5.45, 2.16-5.60 for 60%, 80% and 100% penetration, respectively. In general, as the penetration rate and area replacement ratio increases, the stress concentration ratio tends to increase.

GCP로 개량된 복합지반의 지반강도 별 응력 및 침하거동

나승주(Seung-Ju Na),김대현(Daehyeon Kim),김경업(Gyeong-Eop Kim) 한국지반신소재학회 2017 한국지반신소재학회 논문집 Vol.16 No.3

쇄석다짐말뚝(GCP)은 수십 년 동안 사용되어 왔지만, 팽창, 전단파괴와 기타 현상과 같은 파괴가 여전히 발생하여 보다 정교한 연구가 필요한 실정이다. 본 연구에서는 선행연구 분석과 수치해석을 통해 치환율과 지반강도에 따른 응력 및 침하거동을 분석하고자 하였다. 이를 위해 유한요소해석 프로그램 ABAQUS를 사용하여 GCP로 개량된 복합지반을 모델링하여 지반강도와 치환율에 따라 복합지반의 응력과 침하를 분석하였다. GCP로 개량된 복합지반에 대하여 유한요소법을 이용한 수치해석을 실시하였으며, 치환율과 지반강도에 따른 복합지반의 응력관련계수와 침하저감계수의 관계를 분석하였다. 분석결과, 지반강도와 치환율이 증가할수록 깊이 별 평균 응력관련계수와 응력분담비는 증가하는 경향이 나타났다. 상부에서의 응력관련계수는 동일하게 증가하는 경향이 나타났지만, 응력분담비는 감소하였다. 따라서 상부층에서의 값은 다른 깊이에서의 값들과 다른 경향이 나타나므로 상부층에서의 측정된 값으로 복합지반 설계시 과오를 범할 수 있으니 주의가 필요하다. 또한 기존 침하저감계수식과 수치해석을 통한 침하저감계수와 비교·분석하였는데, 기존 식과 수치해석을 통하여 구한 값은 유사하게 나타났다. Although the Granular Compaction Pile (GCP) has been used for many decades, several failures still occur such as bulging, shear failure and other phenomena, indicating that more refined study is needed. The main objective of the study is to evaluate the stress concentration ratio for both area replacement ratio and shear strength of soil through literature review and numerical analysis. Numerical analysis using the finite element program ABAQUS has been performed for the composite ground with GCP. The behavior stress and settlement of composite ground have been analyzed for both the area replacement ratio (10~40%) and shear strength of soil (25~75 kPa). As a result of numerical analysis, as the soil strength and area replacement ratio increased, the average stree related coefficient and stress concentration ratio for depth tended to decrease, and stress related coefficient of upper layer tend to decrease equally, but the stress concentration ratio decreased. Therefore, tendency that the value in th upper layer differs from the value in other depths was displayed. Care should be taken because it is possible to make mistakes in designing the entire composite ground with the values measured in the upper layer. Also, the settlement reduction factor was compared with the existing equation and numerical analysis. And the value obatined from the existing equation and numerical analysis are similar.

잎담배 단백태 질소 분석법(Mohr법) 개선

김석재,나승주,김지혜,이정래,Kim, Suk-Jae,Na, Seung-Ju,Kim, Ji-Hae,Lee, Jung-Lae 한국연초학회 2011 한국연초학회지 Vol.33 No.1

This study was carried out in order to improve the Mohr method for protein-nitrogen concentration determining. Existing Mohr's method takes seven hours to analyze for one sample. In order to make up for these things tried to utilize filter bag(F75, ANKOM) for sample treatment. As a result of this implementation, have saved sample loss amount and analyzing time for a quarter comparing with Mohr's method. In addition, it have gotten high efficiency through five samples hydrolyze per one trial by using ANKOM hydrolysis system with 0.5% acetic acid. Besides, had a good reproducibility for analysis results in relation to nitrogen concentration determining with Dumas methodology. Thus, new Mohr's method takes one day to analyze for 40 sample. It is more efficiency about 6 times compare with existing Mohr's method. And, this modified Mohr's method was verified that is substitutable for the existing Mohr's method in statistical analysis.

GCP로 보강된 복합지반의 유한요소모델링

김대현(Kim, Dae-Hyeon),나승주(Na, Seung-Ju) 한국지반신소재학회 2016 한국토목섬유학회 학술발표회 Vol.2016 No.10

GCP로 보강된 연약지반의 해석적 거동분석

김민석(Min-Seok Kim),나승주(Seung-Ju Na),양열호(Yeol-Ho Yang),김대현(Daehyeon Kim) 한국지반신소재학회 2016 한국지반신소재학회 논문집 Vol.15 No.3

국내 GCP공법은 많은 선행연구가 진행되었으나, 설계자의 경험에 의해 의존하여 설계되고 있는 실정이므로 파괴사례가 종종 보고되고 있다. 이에 따라 명확한 파괴 원인규명 및 파괴예방대책 수립이 어려운 실정이다. 따라서 본 연구에서는 GCP공법의 합리적인 설계법의 제안을 위한 기초단계로써, GCP에 사용되는 최적배합비를 대형직접전단시험을 통해 결정하고, 내부마찰각의 변화에 따른 응력분담비의 변화 및 지반의 수직/수평 침하거동을 수치해석을 통하여 분석하였다. 직접전단 실험결과 쇄석과 모래의 최적배합비는 70:30으로 평가되었다. 수치해석결과 내부마찰각이 증가할수록 응력분담비가 증가하나 일정한 값으로 수렴하고 침하량이 감소하며, 최적배합비로 시공할 경우 측방유동 및 히빙현상의 감소를 유도할 것으로 판단된다. Although many studies on the Granular Compaction Pile (GCP) have been done by many researchers, the GCP design has not been systematically done due to the absence of the rational design methodology. As the GCP design has been mostly done by engineers" own experiences, some failure cases have been reported to occur. For this reason, it is very difficult to confirm definite causes of the failure and establish the prevention plans for the failure. Therefore, this study aims to investigate the optimal mixing ratio of gravel and sand, the effects of the internal friction angle of the GCP on the stress concentration ratio and the vertical and horizontal settlements. In order to analyze the behavior of the soft ground reinforced with the GCP depending on the different design parameters such as the stress concentration ratio and the internal friction angle, a number of finite element (FE) analyses were performed. From the direct shear test, the optimal mixing ratio of gravel to sand was found to be 70:30. Based on the numerical analyses, as the internal friction angle increased, the stress concentration ratio increased and it converged to a constant value. In addition, the larger the internal friction angle, the smaller the settlements. Consequently, the use of the optimal mixing ratio of gravel and sand can lead to reducing both the lateral flow and the heaving phenomenon.

관통률에 따른 GCP 복합지반의 응력거동 분석

김대현(Kim, Daehyeon),나승주(Na, Seung-Ju) 한국지반신소재학회 2017 한국토목섬유학회 학술발표회 Vol.2017 No.4

GCP 보강 복합지반의 침하저감계수에 관한 수치 해석적 연구

김대현(Kim, Daehyeon),나승주(Na, Seung-Ju),김경업(Kim, Gyeong-Eop) 한국지반신소재학회 2017 한국토목섬유학회 학술발표회 Vol.2017 No.10

친환경 그라우트 주입재에 대한 현장투수시험 결과분석

김대현(Kim, Dae-Hyeon),김민석(Kim, Min-Seok),양열호(Yang, Yeol-Ho),나승주(Na, Seung-Ju) 한국지반신소재학회 2016 한국지반신소재학회 학술발표회 Vol.2016 No.4