• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.75-84
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• 2016

Fluid-dynamic design of fluid machinery had heavily relied on empiricism and experimental observations for many years. Since 1980s, thanks to the advancements in Computational Fluid Dynamics (CFD), a variety of flow physics have been revealed. The contribution by CFD is indispensable; however, the challenge is required not only on the advancements in CFD technologies but also innovation of "design (optimization) technologies" because of the complex interactions between 3-D flow fields and the complex 3-D flow passage configurations, etc. This paper presents historical perspective on fluid machinery flow optimization in an industry with some messages for the future.

• Tribology and Lubricants
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• 제13권3호
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• pp.73-84
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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. Currently, the temperature of ER fluid increases and affects the performance of ER clutch when ER clutch is operating. This study was undertaken to estimate this performance variation due to temperature rise of ER fluid. An analytic heat transfer model of concentric cylinder type ER clutch was developed and with this model, effects of changing geometric, kinetic parameters of ER clutch and ER fluid properties were described. In conclusion, compared with neglecting thermal effects, a performance of ER clutch was very differential and for uniform performance of ER clutch, we have to improve thermal stability of ER fluid. ER fluid.

• The Korean Journal of Physiology
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• 제27권1호
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• pp.13-25
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• 1993

To study the regulation of amniotic fluid volume and electrolyte concentration by the Membranes surrounding the amniotic fluid, the rate of $Li^+$ disappearance from amniotic sac of expired fetuses were examined while increasing the amniotic volume and osmolarity in rabbits. After intraamniotic injection of 1 ml isosmotic saline (about 20% of the amniotic fluid volume) containing 15 mM LiCl and 0.5 g/L Censored, the time courses of $Li^+$ and Censored disappearance were determined. From there the $Li^+$ clearance through the extrafetal routes was estimated and compared with that obtained from living fetuses. The volume, $Na^+$ concentration and osmolarity of amniotic fluid were measured and their relationships with $Li^+$ disappearance were evaluated. The fellowing results were obtained: 1. The rate of disappearance from amniotic fluid of living fetuses during the first 30 minutes was strikingly higher for $Li^+$ than for Censored, suggesting that extrafetal routes exist. At 60 and 90 minutes, however, the disappearance rate of $Li^+$ was less than that of Censored, suggesting the possibility of $Li^+$ reentry through fetal urination. 2. The disappearance of $Li^+$ from the amniotic fluid of the expired fetus was substantial, although lower than that of living fetuses, throughout the experimental period. 3. The $Na^+$ concentration and the osmolarity of the amniotic fluid of expired fetus measured 30 minutes after an intraamniotic injection of isoosmotic saline showed wide variation, but thereafter they changed gradually towards the normal extracellular fluid level. 4. When the amniotic fluid was iso- or hyposmolar, the rate of $Li^+$ disappearance from the amniotic fluid of the expired fetuses showed little variation. However, when the amniotic fluid was hyperosmolar, the rate at 30 minutes was markedly lower than those of isosmotic or hyposmotic amniotic fluid. At 90 minutes, the rate of $Li^+$ disappearance in hyperosmolar fluid reached a similar level to the rate in isosmolar fluid. 5. The intraamniotic injection of 400 mOsm/L saline solution decreased the disappearance rate of $Li^+$ from expired fetuses, while the injection of mannitol into the maternal vein induced no significant change. From these results it is concluded that: 1) a significant amount of $Li^+$ may leave the amniotic fluid via filtration through the membranes surrounding the amniotic fluid, 2) during hyperosmolar challenge to amniotic fluid, osmotic bulk flow might counteract the filterable loss, and 3) $Li^+$ disappearance might continue even after the volume and osmolarity of the amniotic fluid have recovered to control values.

• 한국가축번식학회지
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• 제21권2호
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• pp.111-116
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• 1997

We determined the effects of follicular fluid fractions in the maturation medium on bovine oocyte maturation, fertilization and subsequent development, as well as on number of cells in blastocysts following culture. Follicular fluid and oocytes from bovine follicles less than 5 mm in diameter were collected from the ovaries of slaughtered cows. Follicular fluid was separated into different molecular weight fractions by untrafiltration through a membrane using a centrifuge at 500$\times$g, for 2h. For the maturation medium, follicular fluid fractions (30%, v/v), whole fluid (30%) or PVP(3mg/ml) were added to TCM 199(0.1$\mu\textrm{g}$/ml estradiol-17$\beta$, 100IU hCG). After maturation for 24h, oocytes were fertilized in vitro with bull frozen-thawed spermatozoa and cultured on a monolayer of granulosa cells for 9 days after fertilization. There were no differences in maturation rates or fertilization rates among any maturation conditions. The rates of development to >2-cell stage of the oocytes were significantly decreased when fraction of follicular fluid below 10,000 MW were added into maturation medium, compared with control and fraction above 10,000 MW(26.0% vs 40.8% to 64.0%, respectveily. p<0.01). Likewise, the rates of development to blastocysts of fertilized oocytes were significantly decreased in maturation medium containing fraction of follicular fluid (<10,000 MW). The average cell number of blastocysts derived from oocytes that matured in the fraction(>10,000 MW) of follicular fluid was 154.7$\pm$13.7. These embryos contained more cells than those matured in whole follicular fluid, or the fraction(<10, 000 MW) of follicular fluid or control(107.0$\pm$8.4, 91.8$\pm$11.8 and 95.8$\pm$6.2, respectively). In conclusion, we found that fractions of follicular fluid contained factors stimulating or inhibiting oocyte cytoplasmic matruation. These suggest that a factor(s) inducing cytoplasmic maturation of oocytes may exist in >10,000 MW fraction of follicular fluid.

• International Journal of Fluid Machinery and Systems
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• 제9권2호
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• pp.159-159
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• 2016

• 한국수학교육학회지시리즈D:수학교육연구
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• 제4권2호
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• pp.57-62
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• 2000

we motivate the of the velocity field of a fluid in three ways: from a calculation of the velocity of a rotating fluid relative to a coordinate system rotating with the fluid and from two calculations of a vector form of circulation in small circles or spheres suspended in a moving fluid.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 12th Asian Congress of Fluid Mechanics
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• pp.67.1-67.1
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• 2008

• Clinical and Experimental Reproductive Medicine
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• 제27권2호
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• pp.151-157
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• 2000

Objective: The purpose of this study was to evaluate the effect of polycystic ovarian follicular fluid on sperm motility in human in vitro fertilization (IVF). Methods: From May, 1998 to July, 1999, 55 patients who complained of infertility were involved in this study. We obtained ovarian follicular fluids from the patients by ultrasono-guided aspiration. Subjects were divided into two groups. 20 patients who had polycystic ovarian disease were belong to study group, and 25 patients who had normal ovarian follicular fluid were belong to control group. The follicular fluid dilution was done with Ham's fluid as 10%, 20%, 50%, 100%. The sperm motility was analyzed by CASA at 6hr and 12hr after incubation in follicular fluids. Results: The levels of average path velocity (VAP) in all concentration fluid didn't show significant difference between study and control group. The other parameters including curvilinear velocity (VCL), amplitude of lateral head displacement (ALH), and linerity (LIN) were didn't show any significant difference between both groups. Conclusion: PCOD fluid had seemed to have an adverse effect on the sperm biological function. But, this study showed that PCOD fluid had no different effect on sperm motility with normal follicular fluid.

• 한국해양공학회지
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• 제15권2호
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• pp.135-140
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• 2001

A simply supported pipe conveying fluid and a moving mass upon it constitute a vibrational system. The equation of motion is derived by using Lagrange's equation. The influence of the velocity and the inertia force of a moving mass and the velocities of fluid flow in the pipe have been studied on the dynamic behavior of a simply supported pipe by numerical method. The velocities of fluid low are considered within its critical values of the simply supported pipe without a moving mass upon it. Their coupling effects on the transverse vibration of a simply supported pipe are inspected too. as the velocity of a moving mass increases, the deflection of midspan of a simply supported pipe conveying fluid is increased and the frequency of transverse vibration of the pipe is not varied. Increasing of the velocity of fluid flow makes the frequency of transverse vibration of the simply supported pipe conveying fluid decrease and the deflection of midspan of the pipe increase. The deflection of the simply supported pipe conveying fluid is increased by a coupling of the moving mass and the velocities of a moving mass and fluid flow.

• 한국전산유체공학회지
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• 제14권2호
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• pp.9-18
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• 2009

The cargo containment system (CCS) for ships carrying cryogenic fluid consists of at least two levels of barriers and insulation layers. It is because, even though there is a small amount of leak through the primary barrier, the liquid tight secondary barrier blocks further leakage of the cryogenic fluid. However, once the secondary barrier is damaged, it is highly possible that the leaked cryogenic fluid flows through the flat joint made of glass wool and reaches the inner hull of the ship. The primary objective of the present study is to investigate the influence of the damage extent in the secondary barrier on the amount of leaked cryogenic fluid reaching the inner hull and the temperature distribution there. Simulation results using a computational fluid dynamics tool were compared with the experimental data for the leaked cryogenic fluid flow and evaporation in the secondary insulation layer. The experimental and computational results suggest that, unless there is a massive leak, the cryogenic fluid mostly evaporates in the insulation layer and does not reach the inner hull in the state of liquid.