• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.63-77
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• 1994

The objective of this work is to investigate fluid mixing phenomena related to pressurized thermal shock(PTS) in a pressurized water reactor(PWR) vessel downcomer during transient cooldown with direct vessel injection(DVI) using test models. The test model designs were based on ABB Combustion Engineering(C-E) System 80＋ reactor geometry. A cold leg small break loss-of-coolant accident(LOCA) md a main steam line teak were selected as the potential PTS events for the C-E System 80＋. This work consist of two parts. The first part provides the visualization tests of the fluid mixing between DVI fluid and existing coolant in the downcomer region, and the second part is to compare the results of thermal mixing tests with DVI in the other test model. Row visualization tests with DVI have clarified the physical interaction between DVI fluid and primary coolant during transient cooldown. A significant temperature drop was observed in the downcomer during the tests of a small break LOCA Measured transient temperature profiles agree well with the predictions by the REMIX code for a small break LOCA and with the calculations by the COMMIX-1B code for a steam line break event.

• Journal of Korea Water Resources Association
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• v.49 no.2
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• pp.121-132
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• 2016

The DAMBRK is applied to Janghyeon and Dongmak reservoirs in Namdaecheon basin, where two reservoirs were failed due to Typhoon Rusa in 2002. Relaxation scheme is added to DAMBRK to consider the tributary cross-section because two reservoirs are in tributary valleys. In addition, this study suggests the method to utilize the reservoir breach formation time of ASDSO (2005) and empirical formulas for peak break outflow from dam to reduce the uncertainty of reservoir breach formulation time. The single break of Janghyeon reservoir and consecutive break of Janghyeon and Dongmak reservoirs with the suggested method are considered. While the breach discharge from reservoirs rushes down, the discharge and water surface elevation along the river are predicted, and the predictions show the attenuation phenomena of reservoir break floodwave. The applicability of the model is validated by comparing the predicted height with field surveyed data, and showing good agreements between predictions and measurements.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.5
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• pp.527-536
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• 2010

Although the bubble-floc agglomerate floated and formed the float layer on the surface of the water in the DAF process, after inducing in the thickening tank a part of the bubble-floc agglomerate come up again to the surface and the other is settled at the bottom of the tank. The bubble-floc agglomerate divided into two group as the scum on the surface and the sludge of the bottom gives rise to operational troubles for the thickening process. In order to find out the cause of break-up and the effective thickening method for sludge from the DAF process, the composition of the bubble-floc agglomerate was investigated and a series of flotation experiments carried out. There was no difference of composition between the scum on the surface and the sludge of the bottom in the thickening tank. The coagulation was not effective to improve the trouble that the bubble-floc agglomerate divided into the scum and the sludge. It was estimated that for the bubble-floc agglomerate of thickening tank the trouble was caused by not the change or the difference of chemical composition but whether the bubble-floc agglomerate hold bubbles. Furthermore, for the effective thickening of sludge from the DAF process, it is required an additional flotation applied the AS ratio depending upon the solid concentration of sludge as the operation parameter.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.199-205
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• 2022

BACKGROUND: The freezing injury by pruning can be reduced by suspending pruning work when severe cold weather (-23 to -49℃) is forecast. Minimum air temperature of the study area, Gunwi region at February 3, 2012 was -21.9℃, and the subzero temperature continued until April 8, 2012. This study was conducted in two years to investigate the effect of delaying winter pruning until full bloom on shoot growth and fruit quality of 'Fuji'/M.9 apple trees. METHODS AND RESULTS: The time of pruning were March 26 for dormant, April 3 for bud break, and May 2 for full bloom. The winter pruning at full bloom significantly reduced fruit weight for two years compared with the control (winter pruning at dormant), and shoot growth was reduced only in the following year. There was no significant effect of delaying winter pruning at bud break on soluble solid content, fruit red color, return bloom, and pruning weight for two years compared with the control. CONCLUSION(S): These results indicated the delaying winter pruning at bud break of 'Fuji'/M.9 apple tree did not offer any disadvantage over comparable dormant pruning, since the fruit quality was not affected. The delayed pruning at full bloom resulted in decreased fruit weight, though shoot growth, fruit quality, and return bloom were not affected by the delayed pruning. So, the delayed pruning should be considered carefully only for the fruit tree orchards in diseases.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.202-209
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• 2015

In this study, we investigated the cumulative effect of low temperature on bud dormancy release and bud break characteristics in 'Campbell Early' grapevine (Vitis labruscana B.) cuttings grown in water culture. Additionally, we observed the development of buds while exposed to low temperatures in an attempt to improve our understanding of dormancy and bud break. The shoots were collected 120 days after full bloom (DAFB; leaf abscission period), and the accumulated chill unit (CU) value was calculated by reducing the temperature to $7.2^{\circ}C$ at 125 DAFB. The rate of bud break was 100% in shoots collected at 150 DAFB, The period until the first bud break was two times longer than in the shoots collected 165 DAFB, and bud break speed was significantly reduced. These results indicate that buds are released from endodormancy after 165 DAFB, because at this point the bud break was complete (bud break rate 100%) and it occurred in a very short time period. During this period, when the low-temperature accumulated value was 321h and 442CU according to the CH and Utah models, respectively. Furthermore, the survival rate of main buds decreased rapidly after 165 DAFB, and survival rate of accessory buds was maintained at more than 90% without seasonal differences. The rate of flower bud formation of main buds was much higher than in accessory buds (1:0.23) before the release from endodormancy at 150 DAFB. The final ratio of accessory buds to main buds was high, 1:1.54, at 255 DAFB. Correlation analysis of each investigated factor revealed that bud survival rate and bud formation rate were related only for the main buds, and there was a close relationship between the survival rate of main bud and time. In addition, the survival rate of main buds was positively correlated to the rate of flower bud formation.

• Korean Institute of Interior Design Journal
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• v.13 no.3
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• pp.197-204
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• 2004

This study aims at the development of a cost management system in building interior projects. Renovation and remodeling is activated and expanded much more being compared with new building construction at present. After Interior project proceeding must get out of simple estimate and assumption, then its be needed a formal work process and computerized cost management. Proceeding a building interior project management was proceed in the office and the field. Cost break down, especially, depend on the field manger and used fiend managing money because its not checked by cost manager in office manger. For this study, cost factors are defined in terms of cost break-down interior works which consist of materials and labors. A data model for cost factors was developed, and a relational database is used to realize cost data management based upon this data model. Data input and output are achieved by internet from both of wired PC and mobile phone. This system can timely display a number of needed reports for cost management that identifies cash flow and predicts budget for cost break-down works in interior projects.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.137-143
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• 2002

In this study we generated digital orthophoto from LIDAR data. To generate digital orthophoto, we make TIN from raw laser scanning data(XYZ point data) and compiled DSM from this TIN. In this procedure much noise appeared along the break lines in DSM and this can give bad effect to the quality of digital orthophoto. Therefore, we applied various techniques which can refine the break line. In the result, we concluded that the fusion of LIDAR DEM of lowland and extracted buildings was adequate to generating DSM. So we generated the digital orthophoto from DSM generated from this technique. In the result of quality test, the positional accuracy of this digital orthophoto was better than the positional accuracy of 1:5,000 map.

• Journal of Radiation Protection and Research
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• v.3 no.1
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• pp.1-5
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• 1978

Investigation is carried out that low-level liquid radioactive wastes which is consisted of long half-life nuclides such as cesium can be treated by Korean clinoptillolite as a kind of zeolites. Column operation using a activated clinoptillolite shows good results in terms of break-through curves and comparing to clinoptillolite classified at WARD in U.S, Korean clinoptillolite shows a tailing phenomena longer than that of WARD. The fixation quantity of radioactivity in Korea clinoptillolite is to be about $75{\mu}Ci/100g$ using a $2.5{\times}10^{-3}{\mu}Ci/ml$ solution.

• Korean Security Journal
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• no.24
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• pp.53-66
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• 2010

This study aims to analyze kinematic variables regarding lateral break-fall quantitatively that can protect the body, prevent the injury and minimize the impact. To this end, three Hapkido, judo athletes of H University with experience of over 5 years were selected. Test was conducted through three dimensional image analysis by checking the time and order the subjects reach a mat. In this study, lateral break-fall was repeated five times and among them, the best movement was selected. The picture shot with high-speed camera was analyzed by using KWON3D ver. 3.1 program through three dimensional coordinate calculation based on DLT method and smoothing process of data. Study results were as follows. 1. With respect to time variables shown in lateral break-fall of A, B, C athletes, there is small difference in temporal variables and in the order the body reaches a mat. With respect to average value, hand is ($0.94{\pm}0.20$), elbow ($0.97{\pm}0.17$), hip ($0.97{\pm}0.18$), back ($0.98{\pm}0.18$), and shoulder ($1.04{\pm}0.16$). Time variable the body reaches a mat in lateral break-fall is in hand, elbow, hip, back and shoulder. 2. With respect to moving distance variables shown in lateral break-fall of A, B, C athletes, hand is ($34.33{\pm}34.59$), elbow ($52.00{\pm}26.06$), hip ($70.00{\pm}15.72$), back ($153.67{\pm}17.93$), and should ($130.67{\pm}29.02$). The fact that this study contributed to improving security martial arts technique and protecting the body by understanding the principle of lateral break-fall movement is of significance. In addition, the fact that this study provided systematic basic data for improving security martial arts technique is significant.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.7
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• pp.645-652
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• 2015

In this study, a method for determining Ramberg-Osgood constants for leak-before-break evaluation was investigated. The Ramberg-Osgood constants were calculated for SA312, TP316, and SA-508 Gr.1a in an operating temperature of $316^{\circ}C$. Incremental plasticity, using stress-strain data obtained from experiment, and deformation plasticity, using the Ramberg-Osgood constants, were considered in a finite element analysis. Using incremental plasticity and deformation plasticity, J-integrals and crack opening displacement values were calculated and compared. By comparing the results of incremental plasticity and deformation plasticity, a suitable method for determining Ramberg-Osgood constants for leak-before-break evaluation was confirmed.