• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1193-1194
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• 2013

• 한국지반공학회논문집
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• 제27권10호
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• pp.5-12
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• 2011

본 연구에서는 해안지역의 지반개량과 통시에 오염된 간극수를 정화하기 위한 방법으로 반응컬럼을 이용한 연직배수 공법의 반응컬럼 길이의 결정을 위하여 제강슬래그의 반응성을 평가하였다. 제강슬래그의 카드륨에 대한 반응성을 초기 농도와 pH의 변화에 따라 실험을 수행하였다. 반응시간에 따른 카드륨의 제거량을 유사이차 반응식을 이용해서 평형흡착량($q_e$)과 유사이차 반응상수($k_2$)를 통해 정량적으로 평가하였다. 필요 반응시간은 유사이차 반응모델에서 계산된 평형흡착량($q_e$)와과 유사이차 반응상수($k_2$)의 곱의 역수로 제안하였다. 필요 반응시간을 이용하여 반응컬럼의 길이를 결정할 수 있을 것으로 판단된다.

• 한국항공우주학회지
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• 제44권4호
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• pp.333-342
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• 2016

액체로켓 추진시스템은 액체 추진제와 액체 산화제의 화학반응을 통해 추력을 발생하는 방식으로써 우주발사체 및 인공위성을 포함한 우주비행체에 광범위하게 적용되고 있다. 일반적으로 사용되는 액체로켓 추진제로는 모노메틸하이드라진/사산화이질소, 액체수소/액체산소 및 RP-1/액체산소 조합 등이 있다. 본 연구의 목적은 액체로켓 추진제의 열화학적 반응을 수치적으로 분석함으로써, 이를 통해 궁극적으로 액체로켓엔진의 설계와 성능에 필요한 유용한 정보를 예측하고자 하는 데 있다. 이를 위해 앞서 언급한 3가지 조합의 연료와 산화제에 대하여 연소반응 후 화학평형상태에 도달했을 때 주요 요소평형반응들의 평형상수 값들을 이용해 최종 생성물의 성분과 화학조성을 계산하였고 그 결과를 이용해 단열화염온도와 로켓성능변수인 비추력을 예측하는 연구를 진행하였다.

• 한국산학기술학회논문지
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• 제14권4호
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• pp.2055-2061
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• 2013

청정대체 에너지로 관심이 고조되고 있는 바이오 에탄올의 경제적 생산은 고유가 시대에 있어 매우 중요하다. 분리공정에서 성공적인 정류탑의 설계에는 정확한 기-액 평형치가 이용된다. 2성분 Ethanol/3-methyl-1-butanol 계에 대하여 정온하 즉 50, 55, 60, 65, 70, 75 및 $80^{\circ}C$에서 2성분 기-액평형측정치를 측정하고, 그 측정치를 이용하여 기액평형치를 추산하는 추산식을 이끌어 내었다. 측정치와 추산치를 비교 검토한 결과 ${\pm}0.0005$, ${\pm}0.0022$의 범위 내에서 잘 일치함을 확인하였다.

• 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.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4571-4584
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• 2022

The analysis of rapid flow transients in Reactor Coolant Pumps (RCP) is essential for a reactor safety study. An accurate and precise analysis of the RCP coastdown is necessary for the reactor design. The coastdown of RCP affects the coolant temperature and the colloidal crud in the primary coolant. A realistic and kinetic model has been used to investigate the behavior of activated colloidal crud in the primary coolant and steam generator that solves the pump speed analytically. The analytic solution of the non-dimensional flow rate has been determined by the energy ratio β. The kinetic energy of the coolant fluid and the kinetic energy stored in the rotating parts of a pump are two essential parameters in the form of β. Under normal operation, the pump's speed and moment of inertia are constant. However, in a coastdown situation, kinetic damping in the interval has been implemented. A dynamic model ACCP-SMART has been developed for System Integrated Modular and Advanced Reactor (SMART) to investigate the corrosion due to activated colloidal crud. The Fickian diffusion model has been implemented as the reference corrosion model for the constituent component of the primary loop of the SMART reactor. The activated colloidal crud activity in the primary coolant and steam generator of the SMART reactor has been studied for different equilibrium corrosion rates, linear increase in corrosion rate, and dynamic RCP coastdown situation energy ratio b. The coolant specific activity of SMART reactor equilibrium corrosion (4.0 mg s^-1) has been found 9.63×10^-3 µCi cm^-3, 3.53×10^-3 µC cm^-3, 2.39×10^-2 µC cm^-3, 8.10×10^-3 µC cm^-3, 6.77× 10^-3 µC cm^-3, 4.95×10^-4 µC cm^-3, 1.19×10^-3 µC cm^-3, and 7.87×10^-4 µC cm^-3 for ²⁴Na, ⁵⁴Mn, ⁵⁶Mn, ⁵⁹Fe, ⁵⁸Co, ⁶⁰Co, ⁹⁹Mo, and ⁵¹Cr which are 14.95%, 5.48%, 37.08%, 12.57%, 10.51%, 0.77%, 18.50%, and 0.12% respectively. For linear and exponential coastdown with a constant corrosion rate, the total coolant and steam generator activity approaches a higher saturation value than the normal values. The coolant and steam generator activity changes considerably with kinetic corrosion rate, equilibrium corrosion, growth of corrosion rate (ΔC/Δt), and RCP coastdown situations. The effect of the RCP coastdown on the specific activity of the steam generators is smeared by linearly rising corrosion rates, equilibrium corrosion, and rapid coasting down of the RCP. However, the time taken to reach the saturation activity is also influenced by the slope of corrosion rate, coastdown situation, equilibrium corrosion rate, and energy ratio β.

• 한국공간구조학회논문집
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• 제20권1호
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• pp.95-102
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• 2020

The structural design of arch roofs or bridges requires the analysis of their unstable behaviors depending on certain parameters defined in the arch shape. Their maintenance should estimate the parameters from observed data. However, since the critical parameters exist in the equilibrium paths of the arch, and a small change in such the parameters causes a significant change in their behaviors. Thus, estimation to find the critical ones should be carried out using a global search algorithm. In this paper we study the parameter estimation for a shallow arch by a quantum-inspired evolution algorithm. A cost functional to estimate the system parameters included in the arch consists of the difference between the observed signal and the estimated signal of the arch system. The design variables are shape, external load and damping constant in the arch system. We provide theoretical and numerical examples for estimation of the parameters from both contaminated data and pure data.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1006-1011
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• 2010

This study was focused on the reactivity of furnace slag against cadmium to design the vertical drain method with reactive column for improving contaminated sea shore sediment. The removal capacity of furnace slag was analyzed using pseudo-second-order model. And the effective parameters of removal test were initial concentration and initial pH. According to equilibrium removal amount and reactive constant calculated by pseudo-second-order model, the removal capacity was analyzed. Equilibrium removal amount of furnace slag was linearly increased as increasing intial cadmium concentration. Because the pH was around 11, the removal mechanism of furnace slag could be both sorption and precipitation. Therefore the removal amount was increased due to initial concentration. pH was increased to around 11 in the case of "No treat", but the pH were 3.8 in the case of "HAc added" and 0.7 in the case of "HCl added". The removal amount was different 4.8, 1.19 and 0.27 mg/g. This results show the pH was major factor to remove cadmium using furnace slag.