• The KSFM Journal of Fluid Machinery
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• v.7 no.1 s.22
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• pp.36-44
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• 2004

Three-dimensional vortical flow and separated flow topology near the casing wall in an axial flow fan having two different tip clearances have been investigated by a Reynolds-averaged Navier-Stokes (RANS) flow simulation. The simulation shows that the tip leakage vortex formed close to the leading edge of the blade tip on suction side grows in the streamwise direction. On the casing wall, a separation line is formed upstream of the leakage vortex center due to the interference between the leakage vortex and main flow. The reverse flow is observed between the separation line and the attachment line generated downstream of the trailing edge, and increased with enlarging tip clearance. The patterns of a leakage velocity vector including a leakage flow rate are also analyzed according to two tip clearances. It is noted that the understanding of the distribution of a limiting streamline on the casing wall is very important to grasp the characteristics of the vortical flow in the axial flow fan.

• Journal of Power System Engineering
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• v.9 no.3
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• pp.50-57
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• 2005

A cross-flow fan is strongly influenced by the various design factors of a rear-guider and a stabilizer. The purpose of this paper is to investigate the effects of a rear-guider and a stabilizer on the surface pressure of a rear-guider in an indoor room air-conditioner using a cross-flow fan. The design factors considered in this paper are a rear-guider clearance, a stabilizer clearance, and a stabilizer setup angle, respectively. The operating condition of a cross-flow fan was controlled by changing the static pressure and flowrate using a fan tester. All surface pressures of a rear-guider are differently distributed according to the stabilizer setup angle, and show a zero value in the flow coefficient, ${\Phi}{\fallingdotseq}0.5$ only of a stabilizer setup angle, $45^{\circ}$. Especially, they show a big negative value in the expansion angle larger than $34^{\circ}$ regardless of a rear-guider clearance, a stabilizer clearance, and a stabilizer setup angle. On the other hand, surface pressures for various stabilizer cutoff clearances are better than those for various rear-guider clearances.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.119-126
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• 2006

Gerotor hydraulic motor is widely used in hydraulic systems due to its low speed, high torque output and compactness in rotational direct driving of a heavy weight. Gerotor is a Planar mechanism consisted of a pair of rotor and circular teeth of stator assembly which forms a closed space, so called a chamber. The motion of rotor relative to the circular tooth is produced by the pressure difference of hydraulic operating fluid between the adjacent chamber. As all active contact points of rotor and circular teeth are subjected to very high sliding friction, a reduction in the performance of the gerotor hydraulic motor can not be avoided. Therefore, the core design parameters of gerotor profile used in hydraulic motors is to minimize a friction force by high contact stresses. The analytical design method of gerotor profile, based on envelope of a family of curves, is proposed. In this study, the influence of the tip clearances on three critical contact points between rotor and circular teeth of stator assembly has been explored by experimental data in this paper. At the same time a improvement method to reduce the friction force is proposed and the tip clearances on three critical points for getting an optimum gerotor profile are also analyzed.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.3
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• pp.47-55
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• 2019

Purpose: This study tries to propose the dimensions and area related to patient bed and surroundings in ICU considering nurses' observation and medical care. Methods: Literature survey, 11 Case studies, some Interviews with nurses and measuring of medical equipments' dimension in ICU have been mobilized in order to deepen the ICU bed area standards. Results: 0.3m clearance between head wall and patient bed is necessary for emergency cases. The minimum distance at the foot of the bed should not be less than 0.9m for EMR cart and medical tray. The clear floor area of one bed and surroundings in open ward is $10.2m^2(3m{\times}3.4m)$. In a single-bed patient room, the minimum clear floor area is $16.0m^2(4m{\times}4m)$. Considering the control of cross infection in ICU, Single bed patient room is recommended. Implications: The result of this study can be applied to the design of ICU and legislation of ICU standard.

• The Korean Journal of Pharmacology
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• v.32 no.2
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• pp.269-281
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• 1996

Pharmacokinetics of prednisolone and prednisone undergoing reversible interconversion were analyzed from the model including this metabolic process. Blood samples were drawn serially upto 12 hours after I,V. bolus injection of 1 mg/kg prednisolone sodium phosphate and prednisone into 8 dogs as a crossover manner. Plasma concentrations of those two steroids were simultaneously measured with the method of HPLC. After injection, plasma concentrations of administered prednisolone and prednisone were declined with a biexponential pattern and their metabolic partner was rapidly formed. Plasma concentrations of those metaboite were decayed in parallel with their parent steroids throught the elimination phase. Apparent clearances of prednisolone and prednisone were $11.1{\pm}2.0\;ml/min/kg$ and $45.9{\pm}6.4\;ml/min/kg$, and they were underestimated by 29.4% and 33.6% compared to their real clearances$(15.7{\pm}4.4\;and\;69.2{\pm}17.7\;ml/min/kg)$ estimated using reversible interconversion model. Apparent volume of distribution of prednisolone$(1.32{\pm}0.43\;L/kg)$ and prednisone$(4.81{\pm}2.75\;L/kg)$ were overestimated by 53.5 and 52.7% and were compared to the real volumes $(0.86{\pm}0.30\;and\;3.15{\pm}2.13\;L/kg)$. Mean residence time of prednisolone$(2.0{\pm}0.61\;h)$ and prednisone$(1.74{\pm}0.74\;h)$ were much longer than the real sojourn time$(0.93{\pm}0.26\;and\;0.88{\pm}0.54\;h)$. Essential clearances In the reversible interconversion were greater as following orders: $Cl_{21}$(44.3 ml/min/kg) > $Cl_{20}$(24.2 ml/min/kg) > $Cl_{12}$ (7.9 ml/min/kg) > $Cl_{10}$(7.8 ml/min/kg). Estimated mean values of RF, EE, $%X^1_{ss}$ and $RHO^2_1$ were $0.31{\pm}0.10$, $1.49{\pm}0.23$, $69.3{\pm}16.7%$ and $0.65{\pm}0.10$, respectively. These results suggested that true pharmacokinetic parameters estimated from the model including reversible interconversion were significantly different from the apparent parameters estimated from the conventional mamillary model, and disposition of these two steroids seemed to be well explained by the model including reversible interconversion.

• Biomolecules & Therapeutics
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• v.2 no.3
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• pp.229-235
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• 1994

In dogs, renal denervation did not affect the diuretic action accompanied with renal hemodynamic chanties and inhibition of electrolytes reabsorption rates in renal tubules by methoxyverapamil infused into the vein or into a renal artery, while renal denervation blocked the antidiuretic action due to the decreased free water and osmolar clearances along with the reduced sodium amounts excreted in urine by methoxyverpamil infused into the carotid artery. These experimental results suggest that methoxyverapamil may cause diuresis by direct action in kidney but the antidiuretic action through central function mediated by renal nerves.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.170-177
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• 1995

The restraining characteristics for the single square drawbead are discussed. The drawbead restraining forces adn maximum strains by the various drawing angles are measured experimentally. During this procedure , the drawing angles are varied from 0$^{\circ}C$ to 60$^{\circ}C$. Also, the wide range of experimental data of the drawing forces and maximum strains for the various drawbead dimensions, dimensions, clearances and blank holding forces are preseted.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.211-223
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• 1995

The purpose of the present study is to examine shearing mechanism through rigidplastic finite element analysis. Difficulties arise in simulating shearing process due tothe narrow shear band formation andlackof proper fracture resolve these difficulties by using adaptive mesh generation crriterion. The simulation results are obtained for various punch clearances and these are compared with existing experimental results. It is shown that FEM simulation technique can be used to further understand the shearing mechanism.

• YAKHAK HOEJI
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• v.31 no.6
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• pp.399-401
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• 1987

A gas chromatographic utilizing procedure headspace gas analysis is performed to study effect of malotilate on levels of ethanol and its metabolite acetaldehyde in a blood sample from the rat. The concentrations of ethanol and acetaldehyde were determined simultaneously at 1, 3, and 6h after ethanol administration. Our results would suggest the malotilate could promote clearances of ethanol and acetaldehyde in blood, and could accelerate it, especially, in $CCl_4$ pretreated rats.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.385-396
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• 2000

The secondary motion of piston occurs due to the transient forces and moments in the clearances between piston skirt and cylinder liner The motions are very related to the skirt profile and the magnitude of piston-pin offset. Above all, the elastic deformation is another major effect on the piston secondary motion that has not been considered in the previous researches. In this work, the effects of elastic deformation of the piston skirt on the secondary piston motion are studied for the frictional power loss by using commercial softares, PISDYN and ANSYS.