• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.35-48
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• 2009

An excessive ground displacement occurs with excavating tunnel in a fault zone because the fault has properties of soft ground in generally. It may have had a bad influence to adjacent structure. So, rapid reduction of ground strength by groundwater inflow should be prevented. It must be established for an impervious and reinforcing effect of ground to ensure a tunnel stability. The ground settlement and reinforcing effects were estimated by numerical analyses on tunnel through 570 m sector in Yangsan fault zone of Keongbu high-speed railway. Settlements evaluated by numerical analysis is similar to those calculated by using equation of Loganathan & Poulo. It was shown that reliable estimate of ground settlement by applying a prediction equation is possible. Applicability of adopted tunnel reinforcement method in fault zone was investigated by results of pilot construction and numerical analysis. Results from this study indicate that the adopted reinforcement method make tunnel displacements and member stresses restrain in design criteria.

• Journal of the Korean Geotechnical Society
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• v.18 no.3
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• pp.5-12
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• 2002

Hydraulic conductivity k is one of the most important engineering properties of soil. However, both field and laboratory procedures fur the determination of k are often tedious and expensive. This paper presents new models to predict k using statistical parameters from grain size distribution. A number of permeability tests far 36 types of sands mixed based on statistics were conducted to develop the regression-based models. Parameters used to estimate k are both the geometric mean and geometric standard deviation of the soil samples, or the particle-size distribution curve parameters such as D_{10},D_{50},D_{60}. Hydraulic conductivity predicted by this model is in good agreement with the laboratory measurements fir the soil samples obtained at 20 locations within the Korean Peninsula. The performances of the proposed models were also compared with those of existing models including Hazen's.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1087-1094
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• 2008

This article presents a multi-scale simulation approach starting from the molecular level for the adsorption process development, specifically, in n-hexane adsorption on activated carbon. A grand canonical Monte-Carlo(GCMC) method is used for the prediction of adsorption isotherms of n-hexane on activated carbon at the molecular level. Geometric effects and hydrodynamic properties of the adsorption column are examined by means of the two dimensional CFD(computational fluid dynamics) simulation. The adsorption isotherms from the molecular simulation and the axial diffusivity from the CFD simulation are exploited for the process simulation where the elution curve of n-hexane is obtained. For the first moment(mean residence time) of the pulse-response with respect to temperature and flowrate, the process simulation results obtained from this three-steps multiscale simulation approach show a good agreement with experimental data within 20% of maximum difference. The multi-scale simulation approach addressed in this study will be useful to accelerate the adsorption process development, while reducing the number of experiments required.

• Smart Structures and Systems
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• v.17 no.4
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• pp.593-610
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• 2016

In this study, an innovative and smart glass fiber-reinforced polymer (GFRP) hybrid bar was developed for stronger durability of concrete structures. As comparing with the conventional GFRP bar, the smart GFRP Hybrid bar can promise to enhance the modulus of elasticity so that it makes the cracking reduced than the case when the conventional GFRP bar is used. Besides, the GFRP Hybrid bar can effectively resist the corrosion of conventional steel bar by the GFRP outer surface on the steel bar. In order to verify the bond performance of the GFRP hybrid bar for structural reinforcement, uniaxial pull-out test was conducted. The variables were the bar diameter and the number of strands and pitch of the fiber ribs. Tensile tests showed a excellent increase in the modulus of elasticity, 152.1 GPa, as compared to that of the pure GFRP bar (50 GPa). The stress-strain curve was bi-linear, so that the ductile performance could be obtained. For the bond test, the entire GFRP hybrid bar test specimens failed in concrete splitting due to higher shear strength resulting in concrete crushing as a function of bar deformation. Investigation revealed that an increase in the number of strands of fiber ribs enhanced the bond strength, and the pitch guaranteed the bond strength of 19.1 mm diameter hybrid bar with 15.9 mm diameter of core section of deformed steel the ACI 440 1R-15 equation is regarded as more suitable for predicting the bond strength of GFRP hybrid bars, whereas the CSA S806-12 prediction is considered too conservative and is largely influenced by the bar diameter. For further study, various geometrical and material properties such as concrete cover, cross-sectional ratio, and surface treatment should be considered.

• Food Science and Preservation
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• v.12 no.1
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• pp.54-61
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• 2005

The absorption characteristics and their physical properties of hot air, vacuum and freeze dried soybean curd powder were investigated. Absorption conditions were at 5, 15, and 25 t with $0.11\~0.93$ water activities. Equilibrium moisture content and the monolayer moisture content determined by prediction models showed highest value in the freeze dried soybean curd powder due to porous structure. Absorption energy decreased with increasing water activity was not affected by drying method. In the comparisons of the isothermal absorption models, Oswin model generally was the best fit model for isothermal adsorption of soybean curd powder.

• The Journal of the Petrological Society of Korea
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• v.26 no.1
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• pp.93-98
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• 2017

In this paper, we propose a lava flow simulation program to predict the range of lava flows area and thickness of lava flows during volcanic eruptions. The map information is represented as a 'cell' with observed values per fixed area such as DEM and a lava flow prediction algorithm using a cellular automata model is performed to predict the flow of lava flows. To obtain quantitative data of lava flows, fluid properties of lava flows are defined as Bingham plastic fluid and derived equation is applied to the rules of cellular automata. To verify the program, we use a 30m resolution DEM provided by USGS. We compared simulation results with real lava flows for the Pu'u'O'o crater area in Hawaii, which has erupted since May 24, 2016.

• Fire Science and Engineering
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• v.33 no.5
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• pp.1-6
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• 2019

The recent development of biofuel production technology facilitates the widespread use of bioethanol and biodiesel by mixing them with fossil fuels. However, the use of these new blended fuels in combustion could result in severe safety problems, such as fire and explosion. In this study, numerical simulation was performed on the well-stirred reactor (WSR) to simulate the autoignition temperature (AIT) in homogeneous combustion and clarify the effect of ethanol addition on the AIT, the most important property for assessing the potential for fire and explosion. Response surface methodology (RSM) was introduced as a design of experiment (DOE), enabling the AIT to be predicted and optimized systematically with respect to three independent variables: ethanol mole fraction, equivalence ratio, and pressure. The results show that the autoignition temperature primarily depends on the ethanol mole fraction and pressure, while the effects of the equivalence ratio are independent of the AIT. RSM accurately predicted the experimental AIT, indicating that this method can be used to effectively predict the key properties involved in fires and explosions.

• Journal of Ginseng Research
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• v.39 no.2
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• pp.141-147
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• 2015

Background: Adipocytes, which are the main cellular component of adipose tissue, are the building blocks of obesity. The nuclear hormone receptor $PPAR{\gamma}$ is a major regulator of adipocyte differentiation and development. Obesity, which is one of the most dangerous yet silent diseases of all time, is fast becoming a critical area of research focus. Methods: In this study, we initially aimed to investigate whether the ginsenoside Rf, a compound that is only present in Panax ginseng Meyer, interacts with $PPAR{\gamma}$ by molecular docking simulations. After we performed the docking simulation the result has been analyzed with several different software programs, including Discovery Studio, Pymol, Chimera, Ligplus, and Pose View. All of the programs identified the same mechanism of interaction between $PPAR{\gamma}$ and Rf, at the same active site. To determine the drug-like and biological activities of Rf, we calculate its absorption, distribution, metabolism, excretion, and toxic (ADMET) and prediction of activity spectra for substances (PASS) properties. Considering the results obtained from the computational investigations, the focus was on the in vitro experiments. Results: Because the docking simulations predicted the formation of structural bonds between Rf and $PPAR{\gamma}$, we also investigated whether any evidence for these bonds could be observed at the cellular level. These experiments revealed that Rf treatment of 3T3-L1 adipocytes downregulated the expression levels of $PPAR{\gamma}$ and perilipin, and also decreased the amount of lipid accumulated at different doses. Conclusion: The ginsenoside Rf appears to be promising compound that could prove useful in antiobesity treatments.

• Spatial Information Research
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• v.20 no.3
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• pp.57-66
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• 2012

Gangwon-do has been suffering extensive landslide dam age, because its geography consists mainly of mountains. Analyzing the related factors is crucial for landslide prediction. We digitized the landslide and non-landslide spots on an aerial photo obtained right after a disaster in Inje, Gangwon-do. Three landslide factors-topographic, forest type, and soil factors-w ere statistically analyzed through GIS overlap analysis between topographic map, forest type map, and soil map. The analysis showed that landslides occurred mainly between the inclination of $20^{\circ}$ and $35^{\circ}$, and needleleaf tree area is more vulnerable to a landslide. About soil properties, an area with shallow effective soil depth and parent material of acidic rock has a greater chance of landslide.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.1
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• pp.21-26
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• 2013

This study presents new analysis method to predict bending behavior of packaging substrate structure by comparing finite element method simulation and measured curvature using 3D scanner. Packaging substrate is easily bent and deflected while undergoing various processes such as curing of prepreg and copper pattern plating. We prepare specimens with various conditions and measure contours of each specimen and compute the residual stresses on deposited films using analytical solution to find the principle of bending. Core and prepreg in packaging substrate are made up of resin and bundles of fiber which exist orthogonally each other. Anisotropic material properties cause peculiar bending behavior of packaging substrate. We simulate the bending deflection with finite element method and verify the simulated deflection with measured data. The plating stress of electrodeposited copper is about 58 MPa. The curing stresses of solder resist and prepreg are about 13 MPa and 6.4 MPa respectively in room temperature.