• Nuclear Engineering and Technology
• /
• v.26 no.1
• /
• pp.19-31
• /
• 1994

The objective of this study is to conduct a thermal-hydraulic analysis on the spent fuel pool and to evaluate a parametric effect for the thermal-hydraulic analysis of spent fuel pool. The selected parameters are the Reynolds Number and the gap flow through the oater gap between fuel cell and fuel bundle. The simplified flow network for a path of fuel cells is used to analyze the natural circulation phenomenon. In the flow network analysis, the pressure drop for each assembly from the entrance of the fuel rack to the exit of the fuel assembly is balanced by the driving head due to the density difference between the pool fluid and the average fluid in each spent fuel assembly. The governing equations ore developed using this relation. But, since the parameters(flow rate, pressure loss coefficient, decay heat, density)are coupled each other, iteration method is used to obtain the solution. For the analysis of the YGN 3&4 spent fuel rack, 12 channels are considered and the inputs such as decay heat and pressure loss coefficient are determined conservatively. The results show the thermal-hydraulic characteristics(void fraction, density, boiling height)of the YGN 3&4 spent fuel rack. There occurs small amount of boiling in the cells. Fuel cladding temperature is lower than 343.3$^{\circ}C$. The evaluation of parametric effect indicates that flow resistances by geometric effect are very sensitive to Reynolds number in the transition region and the gap flow is negligible because of the larger flow resistance in the gap flow path than in the fuel bundle.

• Cartoon and Animation Studies
• /
• s.50
• /
• pp.239-273
• /
• 2018

There have been many topics in gamer research on gamers' game addiction, education, and psychological interest. This paper investigates how to perceive the virtual environment of gamers based on James Gibson 's theories of cognitive science. Gibson's theory is not a stimulus input through individual sensory receptors, but rather a learning process such as establishing a cognitive relationship between perceptual systems, external invariant property separation, behavioral learning, invariant property separation of events, selectiveism development. Based on this analysis tool, I collected and verified gamers' perception of game environment of by FGI survey method. The results of the analysis showed that Gibson 's perceptual learning process was perceived as a virtual environment as in reality, and there was also perceptual difference found only in games. Patterned perception develops in the direction of classifying invariant properties appearing in the game based on the purpose of the game. In this study, it can be seen as a result of the research that FGI interview can be summarized as patterning (typification) perception process based on the goal consciousness of gamers. But,The results of the study suggest that the psychological analysis of the gamer can not be presented by the FGI results alone. In the future, we need a model study to confirm the causality and the verification through statistical analysis.

• Korean Chemical Engineering Research
• /
• v.58 no.3
• /
• pp.458-465
• /
• 2020

Isotherms, kinetics and thermodynamic properties for adsorption of acid fuchsin (AF) dye by activated carbon were carried out using variables such as dose of adsorbent, pH, initial concentration and contact time and temperature. The effect of pH on adsorption of AF showed a bathtub with high adsorption percentage in acidic (pH 8). Isothermal adsorption data were fitted to the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm models. Freundlich isothem model showed the highest agreement and confirmed that the adsorption mechanism was multilayer adsorption. It was found that adsorption capacity increased with increasing temperature. Freundlich's separation factor showed that this adsorption process was an favorable treatment process. Estimated adsorption energy by Dubinin-Radushkevich isotherm model indicated that the adsorption of AF by activated carbon is a physical adsorption. Adsorption kinetics was found to follow the pseudo-second-order kinetic model. Surface diffusion at adsorption site was evaluated as a rate controlling step by the intraparticle diffusion model. Thermodynamic parameters such as activation energy, Gibbs free energy, enthalpy entropy and isosteric heat of adsorption were investigated. The activation energy and enthalpy change of the adsorption process were 21.19 kJ / mol and 23.05 kJ / mol, respectively. Gibbs free energy was found that the adsorption reaction became more spontaneously with increasing temperature. Positive entropy was indicated that this process was irreversible. The isosteric heat of adsorption was indicated physical adsorption in nature.

• Korean Chemical Engineering Research
• /
• v.48 no.4
• /
• pp.519-533
• /
• 2010

Activity oefficients and solubilities of L-Alanine in aqueous solutions containing each of four electrolytes(NaCl, KCl, $NaNO_3$ and $KNO_3$) were measured at 298.15 K. The measurements of activity coefficients were carried out in the electrochemical cell coupled with two ion-selective electrodes(cation and anion), and the solubilities were measured by the gravimetric analysis of saturated solutions in equilibrium with the solid phase of L-alanine. To model the activity coefficients and solubilities of amino acid in the amino acid/electrolyte aqueous solutions, thermodynamic relations of the residual Helmholtz free energy in the amino acid/electrolyte aqueous solutions were developed based on the perturbed-chain statistical associating fluid theory(PC-SAFT) combined with the primitive mean spherical approximation(primitive-MSA). In the present model, it is assumed that the zwitterions of L-alanine are associated with each other and cross-associated with water molecules, and also cross-associated with the cation and anion dissociated from an electrolyte(inorganic salt). The activity coefficients and solubilities of L-Alanine calculated from the theoretical model proposed in this work are found to be well agreeable with experimental data.

• The Journal of the Korea Contents Association
• /
• v.16 no.4
• /
• pp.675-690
• /
• 2016

The current study attempts to empirically identify a theoretical background that effectively explains Korean pop-culture consumption in the Asian Pacific region; particularly, in China. Specifically, this study investigates how globalism, proximity, and modernity, which have been suggested in literature as key theoretical backgrounds for the Korean wave, influence China's motivation to consume the Korean wave and its subsequent consumption of Korean TV programs (e.g., dramas, variety shows, etc.). The findings suggest that the motivation to consume the Korean wave is positively related to globalism and proximity. Modernity, however, is found to have a negative influence on the motivation to consume the Korean wave. That is, the more one holds international values, the more one perceives Korea as similar to China, and the more one holds traditional values, the more motivation one shows to consume the Korean wave. The study also finds that the motivation to consume the Korean wave has a significant impact on the consumption of Korean TV programs. In the revised model, the study suggests that proximity, followed by globalism, has the strongest positive relationship with motivation. Such a finding suggests that a proximity approach could serve as a better theoretical perspective to explain the phenomenon of the Korean wave in China. Regarding the relationships of the demographic/socio-economic variables and the motivation to consume the Korean wave, females, rather than males, the higher the family income one gains, and the lower education level one has had, the more motivation one will show to consume the Korean wave.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.439-439
• /
• 2011

최근 이상기후로 인해 세계의 기후, 날씨가 변화하는 추세이다. 이에 따라 한국, 프랑스, 미국 등 세계 각지에서 이상홍수 및 이상가뭄이 발생하고 이로 인한 재산 및 인명피해가 빈번한 현황이다. 따라서 전 세계적으로 기후변화를 고려하여 홍수피해를 저감하고자 많은 노력을 기울이고 있으며, 그러한 방법 중에서도 특히 설계 또는 계획수립 시에 많이 사용되는 방식으로 수치해석 및 수리실험 방법을 들 수 있다. 특히, 수치해석은 수리실험에 비해 비교적 짧은 시간과 경제적인 장점이 있으므로 많이 이용되는 방법 중의 하나이다. 따라서 본 연구에서는 수치해석을 통해 프랑스 남부에 위치한 니스 지역 Var강의 역사상 가장 큰 실강우에 대하여 다양한 방식의 수치해석을 수행하고 수위 관측지점의 수위자료와 비교분석하고자 한다. 본 연구에서는 대상지역을 프랑스 남부에 위치한 니스지역의 Var강으로 선정하였다. 이 지역은 지중해성 기후에 속해 건조하고 따뜻한 날씨였지만 최근 이상기후로 인해 잦은 강우와 홍수 등이 발생하고 있다. 가장 심한 피해가 발생했던 1994년 11월에 발생한 폭우로 인하여 최대 유량이 $3,500m^3/s$까지 관측 되었으며 이는 평균 유량인 $50~100m^3/s$의 35~70배에 달하는 유량이다. 이 홍수로 인해 Var강 유역의 많은 지역이 물에 잠기고 2개의 수중구조물이 파괴되는 등 많은 피해가 발생하였다. 본 연구에서 사용된 수치모형은 미 공병단의 HEC-HMS와 상용 프로그램인 MIKE11과 ISIS이다. MIKE11과 ISIS는 1차원 수리분석모형 프로그램으로써 흐름, 속도, 유량, 수질, 유사이동 등 개수로에서 여러 수리학적 현상을 분석할 수 있는 프로그램이다. 실제 수위자료와 수치모의를 통한 결과값의 비교를 위해 GIS를 통해 얻은 유출계수, 유로경사, 소유역 분할 등을 이용하고 역사상 가장 크게 발생한 1994년의 실강우 이용하여 HEC-HMS을 통해 수문곡선을 작성한 후 동일한 매개변수를 이용하고 검 보정을 통해 MIKE11과 ISIS를 이용하여 수치모의를 실시하였고 실제 수위자료와 프로그램 MIKE11와 ISIS의 결과값을 분석 및 비교하였다. Var강 유역에서 수치모의를 한 결과, 각 프로그램을 사용한 결과값은 실제 수위자료와 비슷한 경향을 보였으며 또한 동일한 매개변수를 이용하였을 때 각 프로그램을 사용한 결과값도 유사한 경향을 보였다. 검 보정을 실시 한 후 ISIS의 결과값이 실제 수위자료와 더 흡사한 것으로 나타났다.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.20 no.2
• /
• pp.138-149
• /
• 2000

Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi mode conversion of guided wave scattering problems. Time dependent wave forms are obtained through the inverse Fourier transformation of the numerical solutions in the frequency domain. 3D BEM program development is underway to model more practical ultrasonic wave signals. Some encouraging numerical results have recently been obtained in comparison with the analytical solutions for wave propagation in a bar subjected to time harmonic longitudinal excitation. It is expected that the presented modeling techniques for elastic wave propagation and scattering can be applied to establish quantitative nondestructive evaluation techniques in various ways.

• Fire Science and Engineering
• /
• v.28 no.6
• /
• pp.52-57
• /
• 2014

The present study suggests the fundamental method for the prediction time of the fire origin by analyzing the combustion phenomenon of inflammable material in the building structure. The heat release rate (HRR) with time variant is evaluated for the interphone as a inflammable material, which is opted from the fire incidents in the stairwell. the fire dynamics simulator (FDS ver. 6.1) is applied in order to analyze the difference of the smoke inflow time to the downstair from the fire event area with various fire pattern. The results show that the maximum inflow time difference for the case of the interphone made from ABS materials is about 4.93 times with the input conditions of heat flux values and the environment in the FDS for the fixed stairwell which composed of total volume $291.3m^3$, floorage $23.3m^2$ and the height of each floor 2.5 m. This research can be practical information for the application method of simulation scheme with experimental data to the fire Identification.

• Journal of the Korea Concrete Institute
• /
• v.24 no.3
• /
• pp.333-340
• /
• 2012

The current study prepared 9 laboratorial concrete mixes and 3 ready-mixed concrete batches to examine the size and shape effects in compression failure of lightweight aggregate concrete (LWC). The concrete mixes were classified into three groups: normal-weight, all-lightweight and sand-lightweight concrete groups. For each concrete mix, the aspect ratio of circular or square specimens was 1.0 and 2.0. The lateral dimension of specimens varied between 50 and 150 mm for each laboratorial concrete mix, whereas it ranged from 50 to 400 mm with an incremental variation of 50 mm for each ready-mixed concrete batch. Test observations revealed that the crack propagation and width of the localized failure zone developed in lightweight concrete specimens were considerably different than those of normal-weight concrete (NWC). In LWC specimens, the cracks mainly passed through the coarse aggregate particles and the crack distribution performance was very poor. As a result, a stronger size effect was developed in LWC than in NWC. Especially, this trend was more notable in specimens with aspect ratio of 2.0 than in specimens with that of 1.0. The prediction model derived by Kim et al. overestimated the size effect of LWC when lateral dimension of specimen is above 150 mm. On the other hand, the modification factors specified in ASTM and CEB-FIP provisions, which are used to compensate for the shape effect of specimen on compressive strength, were still conservative in LWC.

• Journal of the Korean earth science society
• /
• v.23 no.4
• /
• pp.349-356
• /
• 2002

In an effort to properly assess the validity of spaceborne radar altimeter measurements, we made a direct comparison of two different sea surface heights (SSH) acquired by both Topex/Poseidon (T/P) satellite and in-situ tide-gauges (T/G). This comparative analysis was conducted using the data sets collected from three locations along the eastern coast of Korea which include: Ulleungdo, Pohang, and Sokcho. In the course of the analysis of satellite altimeter, information of SSH was extracted from the T/P MGDR data sets through the application of both atmospheric and geophysical corrections. To compare the T/P data sets in parallel basis, the T/G data sets were averaged using the measured values within the peripheral radius of 55km. When compared among different locations, the compatibility between the two methods was much more significant in an offshore location (Ulleungdo) than the two onshore locations (Pohang, Sokcho). If the low-pass filtered results were compared among the sites, the offshore site exhibited the best correlations between the two methods (correlation coefficient of 0.91) than those of the onshore sites. These large differences in the strength of correlations among different locations are due to the deformation of M2, S2, and K1 tidal components used in the tidal model. In case of the offshore location, the compatibility of the two different methods were improved systematically by the low-pass filtering with an increase of the filtering duration such as up to 200 days.