• Journal of the Society of Naval Architects of Korea
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• v.44 no.3 s.153
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• pp.258-266
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• 2007

CFD calculations are performed for KRISO 3600TEU container ship(KCS) models with different Reynolds numbers. Numerical calculations of the turbulent flows with the free surface around KCS have been carried out at $Re=0.791{\times}106\;and\;Re=1.4{\times}107$ using a standard Fluent package. In both cases, Froude number is fixed with 0.26 and wave elevation is simulated by using the VOF method. The calculated results at $Re=1.4{\times}107\;and\;Re=0.791{\times}106$ are compared with the experiment data of KRISO towing tank test and RIMS CWC test, respectively. Boundary layer thickness and wake field shows Reynolds number differences. There are some changes in wave pattern behind transom stern.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.18 no.1
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• pp.13-19
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• 2011

Purpose: The aim of this study was to evaluate patient satisfaction and indirect marketing effects (recommendation, hospital re-visit intention) and additionally to calculate the expected incomes by clinical nurse specialists (CNS). Methods: Sixty-six patients who had lower varicose vein removal surgery performed at two general hospitals from August 1 to November 30, 2008, were recruited. The effects were evaluated by degree of patient satisfaction, the number of personal recommendations given, rate of hospital re-visit intention, and indirect marketing effects. Indirect marketing effects were calculated as the total cost of surgery multiplied by the score of other variables. Results: The patient satisfaction score was 0.82 for CNS and 0.43 for general nurses (GN). The number of personal recommendations given was 2.5 for CNS and 1.1 for GN. The rate of hospital re-visit intention was 0.31 for CNS and 0.21 fot GN. The ratio of expected incomes between CNS and GN is 2.07 to 1. Conclusion: We found that when a CNS serves a patient, satisfaction, number of personal recommendations, hospital re-visit intention, and indirect marketing effects were higher than those of GN. These results show that CNS have dominant roles and functions and that the effects of CNS employment can be measured using economics parameters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.155-160
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• 1979

Mechanical agitation in fermentation process enhances the fermentation activity of microbes by means of oxygen supply and frequent collision with substrate. However, the fermentation activity of microaerophilic bacteria is inhibited by the excess oxygen resulted from the mechanical agitation. On this account, a a strain of Lactobacillus bulgarius was cultured to know the inhibition effect of the mechanical agitation and determine the optimum conditions for tile process of lactic acid fermentation. The growth rate of L. bulgaricus and the consumption rate of tile substrate revealed an identical pattern in changes. The two rates were constant in the range of the modified Reynolds number of $1\times10^5\;to\;5\times10^5$ while they showed linear increase in the range of the modified Reynolds number of $1\times10^5\;to\;10\times10^5$. Under the conditions of the modified Reynolds number more than $10\times10^5$, the both rates decreased. At the modified Reynolds number of $10\times10^5$, the maximum specific growth rate and the saturation constant of L. bulgaricus were 0.58/hr and 6.74g/l, respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.5
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• pp.323-334
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• 2020

Since boundary layer transition has a significant impact on the aero-thermodynamic performance of hypersonic flight vehicles, capability of accurate prediction of transition location is essential for design and performance analysis. In this study, γ-Re_θt model is improved to predict transition of hypersonic boundary layers and validated. A coefficient in the production term of the intermittency transport equation that affects the transition onset location is constructed and applied as a function of Mach number, wall temperature, and freestream stagnation temperature based on the similarity numerical solution of compressible boundary layer. To take into account a Mach number dependency of transition onset momentum thickness Reynolds number and transition length, additional correlation equations are determined as function of Mach number and applied to Re_θc and F_length correlations of the baseline model. The suggested model is implemented to a commercial CFD code in consideration of practical use. Analysis of hypersonic flat plate and circular cone boundary layers is carried out by using the model for validation purpose. An improvement of prediction capability with respect to variation of Mach number and unit Reynolds number is identified from the comparison with experimental data.

• Plant Resources
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• v.5 no.2
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• pp.141-154
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• 2002

In this experiment, three kinds of mutations(ge, re, and eml )relating to the size of embryos were used to study their generation, genetic mechanism and developmental characteristics, and the interactions between embryo and endosperm were also examined. Giant embryo mutation comprises 7 kinds including the already isolated ge, and ge-2, which share an identical gene site. The SAM and the size of radicule for the ge showed little difference compared to a normal type. The number of embryo cells did not increased as much as it would affect the size of embryo. Therefore, the enlargement of embryo was due to the enlargement of scutellum that originated from the corpulence of each cell. Both F$_1$' s of re ]and odm 49 formed reduce embryos, and other combinations of hybridization showed all wild type of embryo sizes. Accordingly, the odm 49 must have an identical gene site of re 1, while odm 48 and odm 62 have different gene sites. Their shoots and radicules also shrank by the same ratio, however no sign of physical change was noticed. The size of embryo cell showed no change, while the number of cells was the half of that of wild types. The three gene sites of re represent all of them control the size of the entire embryo forming organs. The eml 1 was defined to have temperature sensibilities that the generation of endosperms was active at a high temperature while that was hampered at a low temperature.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.504-507
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• 2011

The inertial migration of a two-dimensional elastic capsule in a channel flow was studied over the Reynolds number range $1{\leq}Re{\leq}100$. The lateral migration velocity, slip velocity, and the deformation and inclination angle of the capsule were investigated by varying the lateral position, Reynolds number, capsule-to-channel size ratio(${\lambda}$), membrane stretching coefficient(${\Phi}$), and membrane bending coefficient(${\gamma}$). During the initial transient motion, the lateral migration velocity increased with increasing Re and ${\lambda}$ but decreased with increases in ${\Phi}$, ${\gamma}$ and the lateral distance from the wall. The initial behavior of the capsule was influenced by variation in the initial lateral position ($y_0$), but the equilibrium position of the capsule was not affected by such variation. The balance between the wall effect and the shear gradient effect determined the equilibrium position. As Re increased, the equilibrium position initially shifted closer to the wall and then moved towards the channel center. A peak in the equilibrium position was observed near Re=30 for ${\gamma}=0.1$, and the peak shifted to higher Re as ${\gamma}$ increased. Depending on the lateral migration velocity, the equilibrium position moved toward the centerline for larger ${\gamma}$ but moved toward the wall for larger ${\Phi}$ and ${\gamma}$.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.810-815
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• 2003

Flow-induced noise propagated from flow over a sphere is numerically investigated for laminar flow at Re = 300 and 425, and for turbulent flow at Re = 3700 and $10^4$, where the Reynolds number is based on the freestream velocity and the sphere diameter. The numerical method used for obtaining the flow over a sphere is based on an immersed boundary method in a cylindrical coordinate system. The Curle’s solutions of the Lighthill’s acoustic analogy with and without the far-field and compact-source approximation are used in order to investigate the noise field from flow over a sphere. Since the drag and lift forces change irregularly in time at Re = 425, 3700 and $10^{4}$, the noise propagates in a complicated manner. At Re = 300, 425 and $10^{4}$, the noise from dipole sources is much larger than that from quadrupole sources. On the other hand, at Re = 3700, the quadrupole source becomes dominant. The temporal variation of the flow-induced noise around a sphere is obtained at some observation points, which shows that the peak frequency corresponds to the Strouhal number associated with the wake instability.

• Membrane and Water Treatment
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• v.14 no.1
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• pp.47-54
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• 2023

In this study, high concentrations of cadmium-containing wastewater were treated by electrodialysis (ED) with a channel stack. The limiting current density (LCD), cadmium removal efficiency, and current efficiency were investigated under each experimental condition according to the Reynolds number (Re), membrane area, and pH. With the increase in the film area to 111, 333, 555, and 777 cm² at Re (109.1), LCDs decreased to 408.11, 44.45, 35.32, and 13.64 A/m², respectively. The highest cadmium removal efficiency (99.6%) and current efficiency were obtained for the membrane area of 111 and 777 cm², respectively. Under changing Re in the pH range of 1 to 4, Re and LCD were proportional under the same pH condition, and pH and LCD tended to be inversely proportional under the same Re condition. Cadmium removal rate was the best at the pH range 3 - 4. It has been found that ED with channeled stacks can be successfully applied to treat wastewater containing high concentrations of cadmium.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.301-307
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• 2012

The characteristics of pressure loss in an asymmetric bifurcating tube were investigated numerically for steady inspiratory conditions. The loss coefficient K calculated for various asymmetry and flow-distribution ratios found in human lung airways showed a power-law dependence on the Reynolds number (Re) and length-to-diameter ratio (L/d), with different exponents for Re $\geq$ 100 and Re < 100. The fundamental characteristics of the asymmetric bifurcation are similar to the case of symmetric bifurcation. In addition, the effect of skewed inlet velocity profiles on the pressure loss was weak, and decreased with an increasing number of bifurcations.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.24-30
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• 2013

Today, the modification of carbon foam for high performance remains a major issue in the environment and energy industries. One promising way to solve this problem is the optimization of the pore structure for desired properties as well as for efficient performance. In this study, using a sol-gel process followed by carbonization in an inert atmosphere, hollow spherical carbon foam was prepared using resorcinol and formaldehyde precursors catalyzed by 4-aminobenzoic acid; the effect of carbonization temperature and re-immersion treatment on the pore structure and characteristics of the hollow spherical carbon foam was investigated. As the carbonization temperature increased, the porosity and average pore diameter were found to decrease but the compression strength and electrical conductivity dramatically increased in the temperature range of this study ($700^{\circ}C$ to $850^{\circ}C$). The significant differences of X-ray diffraction patterns obtained from the carbon foams carbonized under different temperatures implied that the degree of crystallinity greatly affects the characteristics of the carbon form. Also, the number of re-impregnations of carbon form in the resorcinol-formaldehyde resin was varied from 1 to 10 times, followed by re-carbonization at $800^{\circ}C$ for 2 hours under argon gas flow. As the number of re-immersion treatments increased, the porosity decreased while the compression strength improved by about four times when re-impregnation was repeated 10 times. These results imply the possibility of customizing the characteristics of carbon foam by controlling the carbonization and re-immersion conditions.