• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2125-2136
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• 2004

In this paper, a numerical application algorithm for applying the CFAM (Consistent Fluid Added Mass) matrix for a core seismic analysis is developed and applied to the 7-ducts core system to investigate the fluid effects on the dynamic characteristics and the seismic time history responses. To this end, three cases such as the in-air condition, the in-water condition without the fluid coupling terms, and the in-water condition with the fluid coupling terms are considered in this paper. From modal analysis, the core duct assemblies revealed strongly coupled out-of-phase vibration modes unlike the other cases with the fluid coupling terms considered. From the results of the seismic time history analysis, it was also verified that the fluid coupling terms in the CFAM matrix can significantly affect the impact responses and the seismic displacement responses of the ducts.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.57-65
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• 2016

By high speed Liquid Droplet Impingement (LDI) on material, fluid systems are seriously damaged, therefore, it is important for the solution of the erosion problem of fluid systems to consider the effect of material in LDI. In this study, by using an in-house fluid/material two-way coupled method which considers reflection and transmission of pressure, stress and velocity on the fluid/material interface, high-speed LDI on wet/dry material surface is simulated. As a result, in the case of LDI on wet surface, maximum equivalent stress are less than those of dry surface due to damping effect of liquid film. Empirical formula of the damping effect function is formulated with the fluid factors of LDI, which are impingement velocity, droplet diameter and thickness of liquid film on material surface.

• 대한간호학회지
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• 제45권5호
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• pp.773-782
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• 2015

Purpose: The purpose of this study was to explore the experience of fluid management in hemodialysis patients by describing how they manage fluid intake and what affects fluid management. Methods: Purposive sampling yielded 11 patients who have received hemodialysis for one year or longer in one general hospital. Data were collected through in-depth interviews and analysed using Giorgi's phenomenological method. Data collection and analysis were performed concurrently. Results: The findings regarding how hemodialysis patients manage fluid intake were classified into four constituents: 'recognizing the need for fluid control', 'observing the status of fluid accumulation', 'controlling fluid intake and output', 'getting used to fluid management'. The factors that affect fluid management of hemodialysis patients were revealed as 'willpower', 'change in the mindset', 'support system', and 'emotional state'. Conclusion: The study results show that hemodialysis patients manage fluid intake through food and exercise as well as interpersonal relationships. These findings suggest that strategies in the development of nursing interventions for hemodialysis patients should be directed at assisting them in familiarization with fluid management based on an understanding of their sociocultural contexts.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.373-374
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• 2002

Magnetic fluid seals are used in a wide variety of gas and dust sealing applications. However, it is difficult to seal for liquid because of its characteristic. This study will be a basic guide for a magnetic fluid seal for liquid, especially for blood to be practically used in medical instruments such as rotary blood pumps by clarifying its seal properties. Sealing pressure test, durability test, and hemolysis test have been conducted for this seal. In this study, magnetic fluid, sealing fluid, eccentricity ratio, revolution speed were selected as parameters. As results of the tests, it has been found that the properties of magnetic fluid seal depend on the solvent and the saturation magnetization of magnetic fluid. Therefore, the selection of magnetic fluid is important for this seal. It also has been found that eccentricity ratio of the shaft caused harmful effect for seal properties. In conclusion, it has been showed that magnetic fluid seals could be possibly used in medical instruments such as blood pumps when blood come in contact with magnetic fluids.

• 한국안전학회지
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• 제17권2호
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• pp.8-15
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• 2002

In order to investigate the vibration characteristics of fluid-structure interaction problem, we modeled two identical rectangular plates coupled with fluid. A commercial computer code, ANSYS was used to perform finite element analysis and FEM solutions were compared with the experimental results to verify the finite element model. As a result, comparison of FEM and experiment showed good agreement, and the transverse vibration modes, in-phase and out-of-Phase, were observed alternately in the fluid-coupled system. The effect of fluid gap size on the fluid-coupled natural frequency were investigated. It was shown that the mode numbers increased, the normalized natural frequencies monotonically increased. And it was also found that an increase of the fluid gap reduced the coupled natural frequencies for the in-phase modes but increased the coupled natural frequencies for the out-of phase modes, and eventually converged to the results of an infinite fluid gap.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.151-166
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• 1997

ER clutch is a device using ER fluid, so called "intelligent material" and is a controlled system with electric field strength. Current problem of this device is that the temperature of ER fluid increases when ER clutch is operating and affects the performance of ER clutch. This study was undertaken to estimate this performance variation due to temperature increase of ER fluid. Analytic power transmission relationships and the temperature increase model using the rheological model of ER fluid were developed and the dynamic model of proposed ER clutch system was constructed, also. With this relationships, effects of changing geometric, kinetic parameters of ER clutch and ER fluid properties were described and performance variations due to temperature increases of ER fluid were estimated. In conclusion, compared with neglecting temperature increase effects, a performance of ER clutch was very differential. Therefore, to achieve uniform performance of ER clutch, we have to improve thermal stability of ER fluid with a view point of material development and design carefully ER clutch considering temperature increase effects with a view point of mechanical design skill.ign skill.

• 한국생산제조학회지
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• 제21권5호
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• pp.761-766
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• 2012

Abrasive fluid jet polishing processes have been used for the polishing of optical surfaces with complex shapes. However, unstable and unpredictable polishing spots can be generated due to the fundamental property of an abrasive fluid jet that it begins to lose its coherence as the jet exits a nozzle. To solve such problems, MR fluid jet polishing has been suggested using a mixture of abrasives and MR fluid whose flow properties can be readily changed according to imposed magnetic field intensity. The MR fluid jet can be stabilized by imposed magnetic fields, thus it can remain collimated and coherent before it impinges upon the workpiece surface. In this study, MR fluid jet polishing characteristics of fused silica glass were investigated according to injection time and magnetic field intensity variations. Material removal rates and 3D profiles of the generated polishing spots were investigated. From the results, it can be confirmed that the developed MR fluid polishing system can be applied for stable and predictable precise polishing of optical parts.

• 한국해안해양공학회지
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• 제8권1호
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• pp.114-122
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• 1996

간척지 매립에 있어서 최근에는 토사를 해저에서 준설하여 파이프라인을 통해 유송시켜 매립시키는 방법이 많이 쓰여지고 있다. 이러한 경우 토사와 혼합된 유체는 slurry fluid의 성질을 지닌다. slurry fluid는 점성도가 독특한 양상을 보이기 때문에 준설토 유송의 관련수치 산정에는 slurry flow 특성을 반영한 관마찰계수 산정식을 사용해야 한다. 준설토를 함유한 slurry fluid는 주로 함유된 입자의 크기에 따라 Newtonian fluid 또는 non-Newtonian fluid 특성을 갖는데, 본 연구에서는 각 특성조건별로 관마찰계수 산정식을 지수함수 형태로 제시하였으며, 이를 이용하여 준설토 유송을 위한 용량산정에 있어 펌프동력 뿐만 아니라 관경 및 유량에 대하여도 양해법 형태의 산정식을 개발하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.223-224
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• 2007

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.219-220
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• 2010