• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1324-1329
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• 2001

The depression of the external situation like the departure of WTO system and the plan of EEZ proclaim is forcing fishery into improving their fishing condition. By this international and domestic circumstance, development of the sea water cooling apparatus for fish hold storage is demanded sincerely. This study represents the thermal characteristics of the fish hold storage during transportation. The numerical analysis in this study is the finite volume method with the SIMPLE computational algorithm to study the seawater flow behavior in the fish hold storage. The computation were carried out with the variations of the circulating flow velocity and depth of fish hold storage. As the result of the three dimensional simulations, the mean temperature doesn't almost change by the circulating flow rate. find the mean temperature is suddenly changed by the ratio of depth of fish hold storage.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.171-175
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• 1999

the high temperature deformation behavior of 304 stainless steel was characterized by the hot torsion test. Continuous deformation was carried out at the temperature ranges 900-110$0^{\circ}C$ and the strain rate ranges 5x10-2~5/sec. The formulation of the flow stress curves was developed as subtraction form which was based on dynamic softening mechanisms The volume fraction of dynamic recrystallization and the mean grain size could be expressed as a function of deformation variables temperature (T) strain ($\varepsilon$) strain rate ($\varepsilon$) The calculated values of flow stress and mean grain size could be well matched with experimental values.

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.19-29
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• 1998

The calcination reactivity of limestone and physical property changes of calcined lime were investigated with a temperature($720~1000^{\circ}C$ under atmospheric gas($N_2$, $CO_2$) conditions. The mechanisms of mass transport in a lime matrix were represented by the evaporation and condensation (${\gamma}=1.7$) at $1000^{\circ}C$ and the volume diffusion (${\gamma}=2.7$) at $800^{\circ}C$, which was obtained by the specific surface area of calcined lime with sintering conditions. Also, the effect of physical property on the reactivity of sulfation reaction was determined by the changes of pore size with $lime-SO_2$ reaction in this work. The initial sulfation rate of calcined lime increased with increasing temperature, whereas the capture capacity of $SO_2$ exhibited a maximum value at $900^{\circ}C$. The pore volume of sulfated lime was decreased with increasing sulfation time, but the major pores shifted to the distribution of larger size at a temperature of $850{\;}~{\;}1000^{\circ}C$. The mean pore size of sulfated lime based on pore volume decreased gradually at $1000^{\circ}C$; however, it increased with sulfation time up to 40 min and rapidly decreased thereafter.

• Journal of Biosystems Engineering
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• v.40 no.3
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• pp.232-237
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• 2015

Purpose: In Korea, wheat is dried using circulating cross-flow grain dryers. However, there is no research on wheat drying which can be utilized for the dryers. Therefore, this study developed and evaluated a simulation of the circulating cross-flow dryer, and examined the effects of various factors on drying performance. Methods: The simulation program was developed using drying models and was evaluated against wheat-drying experiments with a dryer having a 30-ton capacity. The influence of drying temperature, air volume, and grain falling rate on drying performance were examined through the simulation. Results: The experimental results validated the simulation program by showing the same root mean square error (RMSE) for moisture content (0.286%) and drying rate (0.056%/h) in both the experimental data and the simulation values. The appropriate wheat-drying parameter values, considering drying conditions, were determined to be $50^{\circ}C$ for drying temperature, $500m^3/min$ for air volume, and a grain falling rate of $36.0m^3/h$. Conclusions: The developed simulation program for circulating cross-flow dryers analyzed the influences of performance factors such as drying temperature, air volume, and falling rate on drying performance.

• Transactions of Materials Processing
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• v.8 no.6
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• pp.620-625
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• 1999

A finite element analysis is performed to predict the recrystallized volume fraction and the mean grain size in hot compression of Al-5wt%Mg alloy. In the analysis, a modeling equation of flow stress is assumed as a function of strain, strain rate, and temperature. And the influence of above varibles on flow stress is quantified by using Zener-Hollomon Parameter. In the modeling equation, effects of strain hardening and dynamic recrystallization on microstructure of Al-5wt%Mg alloy are investigated. The predicted results of recrystallized volume fraction and mean grain size are in good agreement with those of microstructures obtained from hot compression tests.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.58-67
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• 2003

An automotive engine cooling system is closely related with overall engine performances, such as reduction of fuel consumption, decrease of air pollution, and increase of engine life. Because of complex reaction between each component, the direct experiment, using a vehicle, takes high cost, long time, and slow response to the system change. Therefore, a computer simulation would provide the designer with an inexpensive and effective tool for design, development, and optimization of the engine cooling system over a wide range of operating conditions. In this work, it has been predicted the thermal performance of the engine cooling system in cases of stationary mode, constant speed mode, and city-drive mode by mathematical modelling of each component and numerical analysis. The components are engine, radiator, heater, thermostat, water pump, and cooling fans. Since the engine model is the most important, that is divided into eight sub-sections. The volume mean temperature of eight sub-sections are simultaneously calculated at a time. For detail calculation, the radiator and heater are also divided into many sub-sections like control volumes in finite difference method. Each sub-section is assumed to consist of three parts, coolant, tube with fin, and air. Hence it has been developed the simulation program that can be used in case of design and system configuration changes. The overall performance results obtained by the program were desirable and the time-traced tendencies of the results agreed fairly well with those of actual situations.

• Journal of the Korean Society of Combustion
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• v.11 no.2
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• pp.28-36
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• 2006

A constant volume combustion chamber was used to investigate the combustion characteristics. of homogeneous charge of methane-air mixture under various initial pressure, equivalence ratio and ignition times. The constant volume combustion chamber(CVCC) mostly has been studied by the experiments of visualization until now. So it is needed the numerical analysis of fluid and combustion characteristics in chamber by the more detail simulation. In this paper, the numerical analysis is tried to approach basically the homogeneous charge combustion phenomena under the various conditions, and the combustion phenomena in chamber is numerically analyzed by the commercial FIRE code. As a results, the combustion phenomena which were mean temperature, OH radical and reaction rate in chamber were investigated and it showed that the smallest flame growth occurs for the lean state and the increase of initial charged pressure condition due to the reduced OH radical.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.330-339
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• 2005

An experimental study on the behavior of droplets impinging on a solid flat surface was carried out in the present study. Breakup of a liquid droplet impinging on a solid surface has been investigated experimentally for various liquids with different properties. The liquid droplet temperature and incident angle were chosen as major parameters. Liquid droplet temperature and incident angle varied in the range from $-20{\circ}C\;to\;30{\circ}C\;and\;from\;30{\circ}\;to\;60{\circ},$ respectively. It was found that the variation of droplet temperature influences upon the mean diameter and uniformity of droplets which were bounced out from the solid surface. With increase of incident angle the dispersion mass fraction increases, causing the decrease of liquid film flow rate. As the liquid temperature increases, dispersion mass fraction increases since the surface tension decreases.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.147-151
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• 2006

Although various automated CBC analyzers with different WBC analytical principles were consequently introduced to clinical laboratory, the specific information concerning the suitability or unsuitability of aging samples is scarce. For this reason, we studied the effect of storage duration and temperature on CBC parameter in SE-9000 (SYSMEX Medical Electronics Co., Ltd., Kobe, Japan), automated CBC analyzer. We tested 32 K3-EDTA specimens with SE-9000 during 72 hours. Specimens were kept at room temperature (RT) and refrigerated and were analyzed at 0 hr, 4 hr, 8 hr, 24 hr, 48 hr and 72 hr after the collection of the specimens. The percentage changes from initial value for each parameters were calculated. Among the CBC parameters, hemoglobin, red blood cell count, mean corpuscular hemoglobin and platelets were stable for the study period at both temperatures. The mean corpuscular volume (MCV), hematocrit (Hct) and red cell distribution (RDW) increased and the mean corpuscular hemoglobin concentration (MCHC) decreased over time at room temperature. These parameters were stable when refrigerated. The leukocyte count was stable during 72hr at RT and when refrigerated. At room temperature, the relative percentages of neutrophils tend to increase, whereas those of lymphocyte and monocytes tend to decrease after 48 hours. When refrigerated, those of neutrophils and monocytes tend to increase, whereas those of lymphocytes tend to decreased over time. CBC parameters of refrigerated specimen were reliable for 72 hr for the exception of differential count from 24 hr but many CBC parameters, such as MCV, Hct, MCHC, RDW and differential count of leukocyte of blood stored at room temperature for 24 hr were unreliable.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.4
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• pp.331-336
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• 1990

In order to evaluate the adaptability of Aardi goats to arid environment, 5 Aardi bucks were deprived of water for four days during spring and summer seasons. The rise in average maximum ambient temperature from $24.8^{\circ}C$ in spring to $35.8^{\circ}C$ in summer caused a significant rise in rectal temperature ($0.3^{\circ}C$), respiratory rate (62%), serum osmolaity (8%) and serum sodium concentration (17%). While, it resulted in a significant decline in dry matter intake (50%), urine volume (74%) and fecal water excretion (60%) compared with their values in spring, but had no significant effect on the volume of drinking water. At the end of the 4-days deprivation period during spring, respiratory rate, dry matter intake and urine volume were reduced by 18, 77 and 91% relative to their average in control goats. The corresponding reduction in summer were 58, 100 and 100%. Serum osmolaity was risen by 15% in spring deprived goats and 29% in summer deprived goats. Rectal temperature rose by a mean value of $1.3^{\circ}C$ only in goats deprived of water in summer. Percent of moisture in the feces declined from 64 in control goats, to 24% in water deprived goats during spring season. The corresponding values in summer were 25 and 6%. These responses of Aardi goats deprived of water in summer indicate that they possess a water economy mechanism enable them to tolerate infrequent drinking in hot-arid environment.