• 한국축산식품학회지
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• 제44권4호
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• pp.934-950
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• 2024

This study addresses the prevalent issue of meat species authentication and adulteration through a chemometrics-based approach, crucial for upholding public health and ensuring a fair marketplace. Volatile compounds were extracted and analyzed using headspace-solid-phase-microextraction-gas chromatography-mass spectrometry. Adulterated meat samples were effectively identified through principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA). Through variable importance in projection scores and a Random Forest test, 11 key compounds, including nonanal, octanal, hexadecanal, benzaldehyde, 1-octanol, hexanoic acid, heptanoic acid, octanoic acid, and 2-acetylpyrrole for beef, and hexanal and 1-octen-3-ol for pork, were robustly identified as biomarkers. These compounds exhibited a discernible trend in adulterated samples based on adulteration ratios, evident in a heatmap. Notably, lipid degradation compounds strongly influenced meat discrimination. PCA and PLS-DA yielded significant sample separation, with the first two components capturing 80% and 72.1% of total variance, respectively. This technique could be a reliable method for detecting meat adulteration in cooked meat.

• 대한기계학회논문집
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• 제13권3호
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• pp.528-537
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• 1989

The objective of this paper is to investigate effects of the specific heat and the diameter of suspending particles on the heat transfer coefficient of two phase turbulent flow with suspension of solid particles in a circular tube with constant heat flux. Heat transfer coefficients of two phase turbulent flow in pipe with suspension of graphite powder were measured with variations of particle sizes and solid-gas loading ratio. Measured data were compared with predictions by numerical analysis in which the turbulece models are closed on the first order level. Results show that heat transfer coefficient increases with increasing the solid-gas loading ratio and the specific heat of suspending material, however, it decreases as the average diameter of particles decreases below $24{\mu}m$.

• 한국태양에너지학회 논문집
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• 제30권1호
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• pp.34-41
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• 2010

Gas hydrates are solid solutions when water molecules are linked through hydrogen bonding and create host lattice cavities that can enclose many kinds of guest(gas) molecules. There are plenty of methane(gas) hydrate in the earth and distributed widely at offshore and permafrost. Several schemes, to produce methane hydrates, have been studied. In this study, depressurization method has been utilized for the numerical model due to it's simplicity and effectiveness. IMPES method has been used for numerical analysis to get the saturation and velocity profile of each phase and pressure profile, velocity of dissociation front progress and the quantity of produced gas. The values calculated for the sample length of 10m, show that methane hydrates has been dissolved completely in approximately 223 minutes and the velocity of dissociation front progress is 3.95㎝ per minute. The volume ratio of the produced gas in the porous media is found to be about 50%. Analysing the saturation profile and the velocity profile from the numerical results, the permeability of each phase in porous media is considered to be the most important factor in the two phase flow propagation. Consequently, permeability strongly influences the productivity of gas in porous media for methane hydrates.

• 한국가스학회지
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• 제4권2호
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• pp.7-14
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• 2000

생산지로부터 LNG 선박으로 수송되어 각 생산기지의 저장탱크로 저장되는 액화천연가스 (LNG; Liquified Natural Gas)는 극저은인 Boiling Point보다 약간 낮은 온도 ($-162^{\circ}C$)로 전송된다. LNG 전송은 배관을 통하여 이루어지며, 이로 인하여 배관 내에는 2상 유동 (2-Phase Flow)이 자주 형성된다. 본 연구에서는 일차적으로 이러한 배관내의 2상 유동대한 압력강하량 계산법을 연구하였고, 단열재와 배관 표면을 통한 외부 열유입량과 그에 따른 BOG (Boil-off Gas) 발생량 계산 방법을 연구하여, 이들을 기반으로 LNG 배관시스템의 열유동 해석 프로그램을 개발하였다. 또한 본 연구 및 프로그램 개발을 토대로 최적의 단열재 두께와 배관 Size를 구할 수 있는 최적 설계 프로그램을 구축하였다. 이는 배관설계 시 주어진 최대 허용 압력 강하량과 BOG 발생량 등의 허용 운전 조건과, 단위 길이 당 배관가격과 단위 부피당 단열재가격을 기준으로 허용 범위 내의 최소 설비 비용을 찾는 최적 설계 방법이다.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.47-50
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• 2014

Voloxidation is a process for converting $UO_2$ into $U_3O_8$ while removing some volatile products in spent fuels (SF). Various oxidative gas conditions including air and mixture of Ar and $O_2$ could be adopted for the process. The gas flows into a reactor under high temperature ($>500^{\circ}C$) and components of SF are reacted with the gas. SF is composed of various components such as actinides, lanthanides, and alkali metals. Therefore, it is of significance to understand their behavior during the reactions for process development. However, due to the limit of available experiments, phase diagram analysis should be preceded. TPP diagram is constructed with respect to temperature-pressure-pressure. It shows a stable phase depending on partial pressures of gas components as well as temperature. In this work, we investigated TPP diagrams for actinides, lanthanides and other oxides to determine stable oxide forms under different gas conditions. The results would be used to set up a material balance under a pyroprocessing scheme of SF and compare the gas conditions for the optimization of fission products removal.

• 한국전산유체공학회지
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• 제13권4호
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• pp.50-57
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• 2008

The prediction of hydrate pellet decomposition characteristics is required to design the regasification process of GTS (gas to solid) technology, which is considered as an economic alternative for LNG technology to transport natural gas produced from small and stranded gas wells. Mathematical model based on the conservation principles, the phase equilibrium relation, equation of gas state and phase change kinetics was set up and numerical solution procedure employing volume averaged fixed grid formulation and extended enthalpy method are implemented. Initially, porous methane hydrate pellet is at uniform temperature and pressure within hydrate stable region. The pressure starts to decrease with a fixed rate down to the final pressure and is kept constant afterwards while the bounding surface of pellet is heated by convection. The predicted convective heat and mass transfer accompanied by the decomposed gas flow through hydrate/ice solid matrix is reported focused on the comparison of spherical and cylindrical pellets having the same effective radius.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.268-275
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• 2008

The prediction of hydrate pellet decomposition characteristics is required to design the regasification process of GTS (gas to solid) technology, which is considered as an economic alternative for LNG technology to transport natural gas produced from small and stranded gas wells. Mathematical model based on the conservation principles, the phase equilibrium relation, equation of gas state and phase change kinetics was set up and numerical solution procedure employing volume averaged fixed grid formulation and extended enthalpy method are implemented. Initially, porous methane hydrate pellet is at uniform temperature and pressure within hydrate stable region. The pressure starts to decrease with a fixed rate down to the final pressure and is kept constant afterwards while the bounding surface of pellet is heated by convection. The predicted convective heat and mass transfer accompanied by the decomposed gas flow through hydrate/ice solid matrix is reported focused on the comparison of spherical and cylindrical pellets having the same effective radius.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.268-275
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• 2008

The prediction of hydrate pellet decomposition characteristics is required to design the regasification process of GTS (gas to solid) technology, which is considered as an economic alternative for LNG technology to transport natural gas produced from small and stranded gas wells. Mathematical model based on the conservation principles, the phase equilibrium relation, equation of gas state and phase change kinetics was set up and numerical solution procedure employing volume averaged fixed grid formulation and extended enthalpy method are implemented. Initially, porous methane hydrate pellet is at uniform temperature and pressure within hydrate stable region. The pressure starts to decrease with a fixed rate down to the final pressure and is kept constant afterwards while the bounding surface of pellet is heated by convection. The predicted convective heat and mass transfer accompanied by the decomposed gas flow through hydrate/ice solid matrix is reported focused on the comparison of spherical and cylindrical pellets having the same effective radius.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.475-479
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• 1996

Diethylcarbamazine (DEC, 1-diethylcarbamyl-4-methylpiperazine) is an antiparasitic piperazine derivative used in the treatment of lymphatic filariasis caused by Wuchereria bancrofti, Brugia malayi or grugia timori. DEC-N-oxide is a major metabolite in humans and has antifilarial activity. In carrying out pharmacokinetic studies, gas chromatographic analysis of DEC in plasma can be complicated by the presence of the metabolite, since the thermally unstable DEC-N-oxide is converted back to a material which coelutes with DEC under the conditions of the analysis. We now report a method to separate DEC-N-oxide from DEC in plasma using solid phase extraction with subsequent gas chromatographic analysis using a nitrogen specific detector. One-diethylcarbamyl-4-ethylpiperazine (E-DEC) was the internal standard. The standard curve of DEC was linear in the range of 10 to 200 ng/ml as described by Y=0.0350+0.0128X, $R^2=0.999$. The limit of quantitation was 4 ng/mL. Reproducibility at 10, 100 and 200 ng/mL concentration points of the standard curve gave coefficient variations of 6.1%, 7.8% and 1.6%, respectively. The recovery following solid phase extraction was 99.3% for DEC and 94.8% for the internal standard. This sensitive and specific analytical method is suitable for pharmacokinetic studies of DEC.

• Bulletin of the Korean Chemical Society
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• 제27권2호
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• pp.231-236
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• 2006

A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 $\mu$L. 60 min extraction time at 25 ${^{\circ}C}$ was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant ($K_{lh}$) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, $\beta$-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.