• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.316-321
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• 1997

The mixing vane effect on the Critical Heat Flux (CHF) is discussed with focus on the vortex now effect. In the subchannel approach, this effect is not quantified by the calculation model, but directly taken into account by the CHF correlation itself through data analysis. The vortex now effect is identified the two Westinghouse correlations, and then the CHF margin issue given rise to by the Vantage-5H design change is evaluated and discussed. It is noted that deficiency about CHF dependency on the vortex flow effect could induce an error in the Departure from Nucleate Boiling Ratio (DNBR) sensitivity Calculation.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.389-397
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• 2015

The effects of mixing vanes (MVs) attached to a grid spacer on the characteristics of air-water annular flows were experimentally investigated. To know the effects, a grid spacer with or without MV was inserted in a vertical circular pipe of 16-mm internal diameter. For three cases (i.e., no spacer, spacer without MV, and spacer with MV), the liquid film thickness, liquid entrainment fraction, and deposition rate were measured by the constant current method, single liquid film extraction method, and double liquid film extraction method, respectively. The MVs significantly promote the re-deposition of liquid droplets in the gas core flow into the liquid film on the channel walls. The deposition mass transfer coefficient is three times higher for the spacer with MV than for the spacer without MV, even for cases 0.3-m downstream from the spacer. The liquid film thickness becomes thicker upstream and downstream for the spacer with MV, compared with the thickness for the spacer without MV and for the case with no spacer.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.1052-1065
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• 2024

Advanced Pressurized Water Reactors (APWRs) and Boiling Water Reactors (BWRs) employ a suppression pool as a heat sink to prevent containment overpressure. Steam can be discharged into the pool through multi-hole spargers or blowdown pipes in both normal and accident conditions. Direct Contact Condensation (DCC) creates sources of momentum and heat. The competition between these two sources determines the development of thermal stratification or mixing of the pool. Thermal stratification is of safety concern as it reduces the cooling capability compared to a completely mixed pool condition. In this work we develop a scaling approach to prediction of the thermal stratification in a water pool induced by steam injection through spargers. Experimental data obtained from large-scale pool tests conducted in the PPOOLEX and PANDA facilities, as well as simulation results obtained using validated codes are used to develop the scaling. Two injection orientations, namely radial injection through multi-hole Sparger Head (SH) and vertical injection through Load Reduction Ring (LRR), are considered. We show that the erosion rate of the cold layer can be estimated using the Richardson number. In this work, scaling laws are proposed to estimate both the (i) transient erosion velocity and (ii) the stable position of the thermocline. These scaling laws are then implemented into a 1D model to simulate the thermal behavior of the pool during steam injection through the sparger.

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.935-944
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• 2003

Forced convective boiling heat transfer coefficients were predicted for an annular flow inside a horizontal tube for pure refrigerants and nonazeotropic binary refrigerant mixtures. The heat transfer coefficients were calculated based on the turbulent temperature profile in liquid film and vapor core considering the composition difference in vapor and liquid phases, and the nonlinearity in mixing rules for the calculation of mixture properties. The heat transfer coefficients of pure refrigerants were estimated within a standard deviation of 14% compared with available experimental data. For nonazeotropic binary refrigerant mixtures, prediction of the heat transfer coefficients was made with a standard deviation of 18%. The heat transfer coefficients of refrigerant mixtures were lower than linearly interpolated values calculated from the heat transfer coefficients of pure refrigerants. This degradation was represented by several factors such as the difference between the liquid and the overall compositions, the conductivity ratio and the viscosity ratio of both components in refrigerant mixtures. The temperature change due to the concentration gradient was a major factor for the heat transfer degradation and the mass flux itself at the interface had a minor effect.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.2
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• pp.190-198
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• 2012

This research evaluated and analyzed the level of acceptability of spinach according to blanching time by testing consumer taste of corresponding countries for the purpose of globalizing Korean food. General taste, appearance, flavor, and texture of spinach blanched for 20 seconds were highly evaluated by Koreans and Japanese ($p$<0.05), who are used to the method of slightly blanching, mixing, and eating spinach. On the other hand, general taste, appearance, flavor, and texture of spinach blanched for 5 minutes was highly evaluated by the French ($p$<0.05), who are used to eating boiled spinach. Concerning the result of JAR, there were clear differences in hardness and boiling level according to country among spinach samples, even though they were blanched for the same time and mixed with the same spices. Koreans and Japanese evaluated that hardness and boiling level of spinach blanched for 20 seconds were proper, whereas the French evaluated that spinach scalded for 20 seconds was too raw and crispy. Under the same context, French consumers evaluated that hardness and boiling level of spinach blanched for 5 minutes was proper, whereas Koreans and Japanese evaluated that spinach blanched for 5 minutes was boiled too much. These results show that familiarity level is an important driver of affecting the preference levels for three kinds of spinach according to country.

• Economic and Environmental Geology
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• v.20 no.4
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• pp.213-221
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• 1987

The Donghae mine locates at Jangjoari, Koseongun, Kyongsang-nam-do. The geology of the mine consists of the upper part of Chin dong Formation conformably overlain by tuffaceous Koseong Formation. These formations are intruded by the granodiorite and the basic dikes. The ore mineralization occurs in the fault breccia pipe at the center of a granodiorite stock. The estimated dimension of the breccia pipe is $7m{\times}70m{\times}200m$. The host rock has distinctive hydrothermal alteration halos consisting hematite zone, chlorite zone, epidote zone and sericite zone from outer zone to the ore vein. The ore mineralization occurred in the three distinctive stages. The ore minerals formed in the first stage are pyrite, sphalerite, chalcopyrite, stannite and tetrahedrite. Galena and arsenopyrite are formed in the second stage. Some sphalerite grains include exsolution dots of the chalcopyrite. It is suggested that the ore mineralization occurred by a boiling of a hydrothermal fluid during its initial stage and subsequent cooling and $CO_2$ fugacity drop of remaining hydrothermal fluid by a ground water mixing aided vertical zoning of the ore minerals.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.97-103
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• 2012

The basic processing unit for instant ramen noodles includes mixing, rolling, boiling, frying, cooling, and packing processes. For uniform thickness of dough sheets in rolling process, the roll-gap in rolling process needs to keep uniform thickness of flour sheets in spite of different kinds of raw materials. In this paper, we have developed a roll gap adjustment system using a PLC (Programmable Logic Controller) with a touch panel and an AC servo-mechanism to make dough sheets with a good gluten starch-network structure and uniform thickness and to contribute to process standardization by transferring from tacit knowledge of skilled workers to explicit knowledge. The developed system can adjust the roll gap in units of 0.01mm and correspond to various product items which have different thickness specification by recalling the presetting values of the desired thickness from database.

• Herbal Formula Science
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• v.7 no.1
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• pp.77-87
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• 1999

We studied medicinal theory on processing drugs of Wang-Ang. Wang-Ang used various methods of medicinal processing. He used such as soaking(浸), maceration(泡), washing(洗), elutriation(淘), mixing together(拌), refining powder with water(水飛) and floating(水漂) in medicinal processing with water. He used such as making hot(?), roasting in ashes(?), stir-frying with liquid(炙), parching(炒), heating(燒), baking(焙), stirring-baking(?) and distilling(煉) in medicinal processing with fire. He used such as steaming(蒸), boiling(煮), making hot and soaking(??) in medicinal processing with water and fire. And He used such as cooking(熟), making drugs into gelatin(制膠), making drugs into frostlike powder(制霜法), making drugs into bead(制珠), fermentation(生衣) and compound medicinal processing(複制法).

• Nuclear Engineering and Technology
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• v.42 no.6
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• pp.636-655
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• 2010

A thermal-hydraulic code, named CUPID, has been being developed for the realistic analysis of transient two-phase flows in nuclear reactor components. The CUPID code development was motivated from very practical needs, including the analyses of a downcomer boiling, a two-phase flow mixing in a pool, and a two-phase flow in a direct vessel injection system. The CUPID code adopts a two-fluid, three-field model for two-phase flows, and the governing equations are solved over unstructured grids with a semi-implicit two-step method. This paper presents an overview of the CUPID code development and assessment strategy. It also presents the code couplings with a system code, MARS, and, a three-dimensional reactor kinetics code, MASTER.

• Journal of ILASS-Korea
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• v.11 no.4
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• pp.234-243
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• 2006

Diesel autothermal reforming (ATR) is a chemical process to produce hydrogen for fuel cell applications. Several previous studies were carried out to identify technical issues in diesel reforming. It is hard to vaporize diesel due to its high boiling points. Liquid droplets of diesel result in inhomogeneous fuel mixing with other reactants such as $O_2\;and\;H_2O$, which leads to reduce the reforming efficiency and make undesired coke in reactor. To solve the fuel delivery issue, we applied an ultrasonic device as a fuel injection system. Ultrasonic injector (UI) remarkably enhanced the reforming efficiency. This paper will present the reforming results using UI. And we will discuss about atomization effects of diesel on autothermal reforming reaction.