• Journal of Environmental Science International
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• v.22 no.5
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• pp.523-531
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• 2013

In this study, a method of simulating ephemeral stream runoff characteristics in Jeju watershed is newly suggested. The process based conceptual-physical scheme is established based on the SWAT-K and applied to Cheonmi-cheon watershed which shows the typical pattern of ephemeral stream runoff characteristics. For the proper simulation of this runoff, the intermediate flow and baseflow are controlled to make downward percolation should be dominant. The result showed that surface runoff simulated by using the modified scheme showed good agreement with observed runoff data. In addition, it was found that the estimated runoff directly affected the groundwater recharge rate. This conceptual model should be continuously progressed including rainfall interception, spatially estimated evapotranspiration and so forth for the reasonable simulation of the hydrologic characteristics in Jeju island.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.4
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• pp.451-459
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• 1998

THe influence of internal acoustic exitation through a square prism on the turbulent wake flow characteristics was investigated. The intermediate wake region where is about ten times the respective length of the body was experimentally investigated using a conditional phase average technique. At first the static base pressures of square prism and the shedding frequencies have been measured at various internal acoustic exciation frequencies. The experiment were performed under the four cases of internal acoustic excitation frequencies 0Hz 30Hz($St_e$=0.09) 65Hz($St_e$=0.20) 120Hz($St_e$=0.38) And velocity vector fields were presented and discussed. The influence of acoustic exvitation frequencies on the structure of intermediate turbulent wake region is evident. As the internal acoustic frequency increased shedding frequency gradually increased and aerodynamic force decreased. Also it was found that the vortex shedding occurs dratically well and shedding frequency reached nearly the same value as the internal acoustic frequency. but above Strouhal number 0.3 the influence disappeared.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.185.1-185
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• 2001

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.12
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• pp.1093-1099
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• 2010

For Very High Temperature Reactors (VHTR), the designs of the Intermediate Heat Transport Loop (IHTL) and the Intermediate Heat Exchanger (IHX) are particularly difficult because of the high-temperature operation (up to $950^{\circ}C$). In this study, Flinak molten salt, a eutectic mixture of LiF, NaF, and KF (46.5:11.5:42.0 mole %) is considered as the heat transporting fluid in the IHTL. To evaluate the flow and heat transfer performance of the Flinak molten salt in small channels with hydraulic diameters in the millimeter range, a double-pipe heat exchanger was constructed using small-diameter tubes for the heat exchange between the Flinak and the gas flow. The experimental data showed that, for laminar Flinak flow, the measured friction factors were close to the 64/Re curve and the Nusselt numbers were generally between 3.66 and 4.36.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.266-271
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• 2001

In this study, the performance of the simultaneous heating & cooling water making system using R134a was investigated by simulation. The most important effect upon heating COP was intermediate pressure depending on input water temperature. With the input water temperature of $10^{\circ}C\;and\;20^{\circ}C$, optimum intermediate pressure were 923 and 1040kPa, respectively. At that optimum intermediate pressure, the maximum heating COP of the system operated between $0^{\circ}C$ evaporating temperature and $70^{\circ}C$ condensing temperature were 4.15 and 3.83. With installation of the subcoolers in high or low pressure section, the system COP was increased by reducing the refrigerant mass flow rate. Under the optimum pressure and $10^{\circ}C$ input water temperature, it was found that heating COP was maximized when the low-subcooler and high-subcooler capacity rate were taken by 14% and 13%, respectively.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.196-202
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• 2016

With increasing LM soybean import, the concern about unintentional gene flow from LM soybean to wild soybean and consequential weedy risk has been growing. Therefore, we conducted this study to characterize seed traits including germination of hybrids resulted from gene flow from LM soybean to wild soybean in comparison with their parents, LM soybean and wild soybean. Pollen-donor LM soybean seeds were much greater and heavier (about 15.0 g of 100 seed weight) than F2 hybrid (5.7 g), while pollen-recipient wild soybean and F1 hybrid seeds were smallest and lightest (about 2.5 g). F2 hybrid was brown, intermediate between yellow LM soybean seed and black wild soybean seed. These findings indicate that F1 hybrid seeds show similar characteristics with wild soybean, while F2 hybrid seeds show intermediate color and size between two parents. F2 hybrid seed showed intermediate traits between two parents in germination and dormancy rates, which were 35% and 65%, respectively. LM soybean showed no dormancy, while wild soybean showed greater than 90% dormancy. This finding indicates that F2 hybrid show intermediate characteristics in seed germination with high dormancy trait, suggesting a potential weediness of hybrids resulted from gene flow from LM soybean to wild soybean.

• Transactions of Materials Processing
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• v.24 no.5
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• pp.340-347
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• 2015

Multi-pass shape drawing is used to manufacture long products of arbitrary cross-sectional shapes. This process allows smooth surface finishes and closely controlled dimensions of the cross-sectional shape. Tube shape drawing for hollow type products provides material savings and weight reduction. The intermediate die shapes are very important in multi-pass tube shape drawing. In the current paper, the design method for the intermediate dies in a tube shape drawing process is developed using a die offset for corner filling (DOCF) method. Underfill defects are related to the radial velocity distribution of each divided section in the deformation zone. The developed intermediate die shape design was applied to the two-pass tube shape drawing with fixed mandrel for manufacturing a hollow linear motion (LM) guide rail. The proposed design method led to uniform and steady metal flow at each divided section. FE-simulations and experiments were conducted to validate the effectiveness of the proposed method in multi-pass tube shape drawing process.

• Nuclear Engineering and Technology
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• v.41 no.10
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• pp.1323-1332
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• 2009

The IHX (Intermediate Heat eXchanger) for a pool-type SFR (Sodium-cooled Fast Reactor) system transfers heat from the primary high temperature sodium to the intermediate cold temperature sodium. The upper structure of the IHX is a coaxial structure designed to form a flow path for both the secondary high temperature and low temperature sodium. The coaxial structure of the IHX consists of a central downcomer and riser for the incoming and outgoing intermediate sodium, respectively. The IHX of a pool-type SFR is supported at the upper surface of the reactor head with an IHX support structure that connects the IHX riser cylinder to the reactor head. The reactor head is generally maintained at the low temperature regime, but the riser cylinder is exposed in the elevated temperature region. The resultant complicated temperature distribution of the co-axial structure including the IHX support structure may induce a severe thermal stress distribution. In this study, the structural feasibility of the current upper support structure concept is investigated through a preliminary stress analysis and an alternative design concept to accommodate the IHTS (Intermediate Heat Transport System) piping expansion loads and severe thermal stress is proposed. Through the structural analysis it is found that the alternative design concept is effective in reducing the thermal stress and acquiring structural integrity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.2
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• pp.169-176
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• 2000

Natural convection in a wide-gap horizontal annulus is considered, and the transition of flows and the bifurcation phenomenon are investigated for the fluids with Pr=0.2 and 0.3. At Pr=0.2, a bicellular flow pattern is observed at high Rayleigh number, and the solution is unique. At Pr=0.3, both the steady unicellular and bicellular flows exist above a certain critical Rayleigh number. For the fluids of Pr=0.2, the bicellular flow can be obtained by the impulsive heating of the inner cylinder, but it is not obtained from the zero initial condition for Pr=0.3. Hysteresis phenomena have not been observed. A transition from a bicellular flow to a unicellular flow occurs for Pr=0.3.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3067-3072
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• 2008

A two-dimensional model for anode-supported IT-SOFCs is proposed in order to accurately consider the heat and mass transport processes with a fully-developed axial velocity profile in channel flow. A comprehensive micro model is employed to describe the electrochemical reaction in anode and cathode of SOFCs. This paper investigates the effects of operational parameters (inlet temperature, the amount of flow rate, and air flow rate) including flow configurations (co-flow and counter-flow) on the current density and temperature distributions in the IT-SOFCs.