• Proceedings of the KSME Conference
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• 2002.08a
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• pp.597-600
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• 2002

In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Uneven flow distribution can also increase or decrease the power consumption with a change in total developed head. To avoid these sump problems pump station designers are considered intake structure dimensions, such as approaching upstream, baffle size, sump width, width of pump cell and so on. From this background, flow characteristics of intake within sump are Investigated numerically to obtain the optimal sump design data. The sump model is designed in accordance with HI code.

• Journal of Industrial Technology
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• v.19
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• pp.59-65
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• 1999

This study is to analyze turbulent flow over a backward-facing step in a rectangular duct. The side wall effects on the internal flow were determined by varying the aspect ratio(defined as the step span-to-height ratio) from 1 to 20. In the flow behind a backward-facing step, separation, recirculation and redeveloping is occurred frequently. These phenomena appear in a particular variation by varying the aspect ratio. The results show that the aspect ratio has an influence on the velocity and reattachment length. When the AR is increased, the reattachment length is increased. For 6 over aspect ration, the rate of increase is decreased. The length of recirculation in the upper corner is increased, as the increase of aspect ration. It's width is not changed in the variation of aspect ration. The transverse, streamwise and spanwise velocities were decreased along the flow down stream of the step.

• Journal of Mechanical Science and Technology
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• v.18 no.12
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• pp.2258-2264
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• 2004

This article described the numerical investigation of shear-thinning blood flow characteristics when subjected to longitudinal and transverse vibrations and delineated the underlying mechanisms of the flow rate enhancements, respectively. In order to fully consider the mechanical vibrations of the capillary, a moving wall boundary condition was adopted. The present numerical results showed that the longitudinal vibration caused a significant increase of wall shear rates, which resulted in a decrease of viscosity and the subsequent increase of flow rates. However, the shear rate for the transverse vibration was slightly increased and the calculated flow rate was underestimated comparing with the previous experimental results.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.5
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• pp.679-685
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• 2009

In order to simulate a smoke or poisonous gas emergency in a rectangular tunnel and to investigate a better way to exhaust the smoke, the characteristics of smoke flow have been analyzed using flow field data acquired by Particle Image Velocimetry(PIV). Olive oil has been used as tracer particles with the kinematic viscosity of air, $1.51{\times}10^{-5}\;m^2/s$. The investigation has done in the range of Reynolds number of 1600 to 5333 due to the inlet velocities of 0.3 m/s to 1 m/s respectively. The average velocity vector and instantaneous kinematic energy fields with respect to the three different Reynolds numbers are comparatively discussed by the Flow Manager. In general, the smoke flow becomes more disorderly and turbulent with the increase of Reynolds number. Kinematic energy in the measured region increases with the increase of Reynolds number while decreasing at the leeward direction about the outlet region.

• The Korean Journal of Pain
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• v.8 no.1
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• pp.55-59
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• 1995

Stellate ganglion block (SGB) is applicated frequently to increase the blood flow and to reduce the pain in head, neck and upper extremity. The effects of SGB are able to be estimated by clinical signs and symptoms of Horner's syndrome, skin warmth, anhydrosis, etc. The effects are also estimated by sympathetic function and the blood flow. Blood flow velocities and pulsatility indices of common carotid,d axillary, brachial and radial artery were measured by Doppler flowmeter after SGB with 1% lidocaine at C6 level. Blood velocities of all arteries were increased and pulsatility indices of all arteries were decreased. This results suggest that SGB increase the blood flow of head and upper extremity and Doppler flowmeter is a good indicator of the effects of SGB.

• YAKHAK HOEJI
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• v.28 no.3
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• pp.149-160
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• 1984

In order to certify the diuretic mechanism of dopamine, this study was performed in dog. The following results were obtained. Dopamine, when given intravenously, produced diuresis, and increased glomerular filtration rate (GFR), renal plasma flow (RPF), and amount of sodium excreted in urine. When infused directly into a renal artery, dopamine elicited a marked diuresis confined only to the infused side, with concomitant rises in osmolar clearance and sodium excretion as well as a slight increase in free water clearance. Simultaneously total renal plasma flow and medullary plasma flow increased markedly with a increase of glomerular filtration rate and renal plasma flow. Medullary concentration gradient of sodium also markedly lowered in the infused kidney. These changes were not observed during mannitol diuresis and renal action of dopamine were not apparent in dog pretreated with haloperidol. From the above experimental results, it is thought that dopamine, when given into a vien or infused directly into a renal artery, induces diuresis, and the mechanism of its action is due to dual actions which are hemodynamic effect along with glomerular filtraction rate, and the increased response in the medullary blood flow.

• Journal of ILASS-Korea
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• v.9 no.4
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• pp.77-82
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• 2004

This paper describes the improvement of engine cooling system. To improve engine cooling performance, the authors approached in two ways. One is to increase water pump performance, changing of impeller shape and lightening of material were carried out. The second one is cooling efficiency rise, which were investigated with head gasket coolant flow passage optimization with flow visualization technique. The test results show that water pump performance was increased effectively, reduction of pump drive torque, and increase of pump flow-rate and pressure rise. Gasket hole pattern optimization test results represent an optimized head coolant flow which stands cross flow from exhaust to intake port side and small vortex were removed.

• The Journal of Korean Academic Society of Nursing Education
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• v.25 no.4
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• pp.393-404
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• 2019

Purpose: This study aims to investigate the influence of personality type, self-leadership, and positive psychological capital on the flow of learning of nursing students. Methods: The sample consisted of 179 nursing students. Data were analyzed using frequency, percentage, mean, standard deviation, t-test, ANOVA, $Scheff{\acute{e}}^{\prime}s$ test, Pearson's correlation coefficient analysis, and Hierarchical multiple regression. Results: Upon analysis, the relative influence of the variables that can improve learning flow, the influencing variables, were identified as self-leadership and self-efficacy. Conclusion: To increase the learning flow, supportive measures and strategies that increase positive psychological capital should be developed, successful cases of self-leadership be shared, and be incorporated into a culture that promotes learning flow. And to promote the learning flow, it needs political and environmental improvement, and institutional support of at the college level.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.435-440
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• 2016

Effects of the increase rate of Reynold number on near-wall turbulent structures are investigated by performing direct numerical simulations of transient turbulent channel flows. The simulations were started with the fully-developed turbulent channel flow at $Re_{\tau}=180$, then temporal accelerations were applied. During the acceleration, the Reynolds number, based on the channel width and the bulk mean velocity, increased almost linearly from 5600 to 13600. To elucidate the effects of flow acceleration rates on near-wall turbulence, a wide range of durations for acceleration were selected. Various turbulent statistics and instantaneous flow fields revealed that the rapid increase of flow rate invoked bypass-transition like phenomena in the transient flow. By contrast, the flow evolved progressively and the bypass transition did not clearly occur during mild flow acceleration. The present study suggests that the transition to the new turbulent regime in transient channel flow is mainly affected by the flow acceleration rate, not by the ratio of the final and initial Reynolds numbers.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.595-600
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• 2001

Thermal mass flow meter(TMF) and thermal mass flow controller(MFC) were used to measure and to control the mass flow rate of gases. TMF and MFC were designed for specified working pressure and gas. For the case of different working pressure and gases, the flow rate measurement accuracy decreased dramatically. In this study, a TMF and MFC was tested with three different gases and pressure range from 0.2 MPa up to 1.0 MPa. Effect of specific heat causes to increase flow measurement error as much as ratio of specific heat compared with reference gas. Changing of pressure causes to increase flow rate measurement error about -0.2% as the working pressure decreased 0.1 MPa. Response time of MFC was below 3.12 s for the case of increasing of flow rate. But the response time was increased up to 6.92 s for the case of decreasing of flow rate. When the solenoid valve was fully closed, a initial delay time of output of MFC was increased up to 1.36 s.