• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.371-372
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• 2002

It is well known that red blood cells (RBCs) are suffered from chronic stresses in systemic circulation. The objective of this study is to clarify the effect of the aging of RBCs on rheological properties and hemolysis. Initially, RBCs age fractionation was performed by using a high-speed centrifugation (15[min] at 1500[G]), then young and aged RBCs were suspended in plasma to adjust the hematocrit level of 40[%]. After this pretreatment, the viscosity was measured by using a capillary type and a cone-plate type viscometers, respectively, and the hemolysis test was carried out by a seesaw type shaker. Results from these experiments showed that the viscosity of the aged RBCs measured by the capillary viscometer was increased by 10[%] as compared with that of the young RBCs. Under the condition of all shear zones, the viscosity of the aged RBCs was increased in case of using the cone-plate type viscometer. And the hemolytic level was increased twice as the aging. The data obtained in this study indicated that the ability of aggregation of RBCs was increased and the deformability of RBCs membrane got lower with the aging. Furthermore, it was exhibited that the fragility of RBCs ’ membrane was increased with the aging.

• 한국수소및신에너지학회논문집
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• 제26권6호
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• pp.581-589
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• 2015

In this study, the viscosity of a liquid carbon dioxide ($LCO_2$) that can potentially be used in a wet feed coal gasifier was evaluated. A pressurized capillary viscometer was employed to obtain the viscosity data of $LCO_2$ using two different methods. During the first method, the measurements were conducted under quasi-steady and high pressure flow conditions where two-phase flow was greatly minimized. The viscosity of $LCO_2$ was determined using turbulent friction relationship. At the second flow condition where unsteady flow is induced, the viscosity of $LCO_2$ was measured using the half-time pressure decay data and was further compared with values calculated by the first method.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1277-1284
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• 2000

To enhance heat transfer characteristics of water, micro-encapsulated octadecane of about $10{\mu}m$ diameter was added to water. Viscosity of the slurry was measured by using a capillary tube viscometer. The measured viscosity decreased as the temperature of the slurry increased, and it increased as the fraction of the capsules in the slurry increased. Thermal characteristics of the octadecane were studied by using a differential scanning calorimeter. The melting temperature and the melting energy of the octadecane were found to be $28.6^{\circ}$ and 34.4kcal/kg, respectively. The convective heat transfer characteristics of the slurry were investigated in a flow loop with a constant heat flux test section. Friction factor of the slurry flow was found to be similar to the expected curve by Petukhov. The Nusselt number of the slurry flow was highest when the octadecane melted. Effective thermal capacity of the 14.2% slurry was found to have 1.67 times of the thermal capacity of water.

• 한국임상수의학회지
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• 제35권3호
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• pp.77-82
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• 2018

The aim of this study was to measure whole blood viscosity (WBV) and then to establish its reference values and identify correlation between WBV and hematology or serum chemistry in beagle. The experiment was made up of 82 healthy beagle dogs. Jugular vein blood samples (10 ml) were collected. WBV (cP) measured within 4 hours after collection by U-shaped scanning capillary-tube viscometer ($BVD-PRO1^{(R)}$) which is capable of measuring yield stress and viscosity of whole blood continuously over a wide range of shear rates from $1s^{-1}$ to $1000s^{-1}$ is new type of capillary tube viscometer and calculates viscosity using Casson fluid model. Measured values of WBV, Complete blood cell count, serum chemistry were analyzed by RM-ANOVA test. Mean diastolic and systolic WBV (cP) were $29.032{\pm}6.137$ and $4.528{\pm}0.865$. Bodyweight (BW), Red blood cell count (RBC), Hemoglobin (HGB), Hematocrit (HCT), Alkaline phosphatase (ALP), Cholestetol (CHOL), Total protein (TP), Globulin, Chloride (Cl), Fibrinogen, were statistically correlated with WBV over whole range of shear rates (p < 0.05). This study newly evaluated reference values of WBV by U-shaped viscometer in beagle. Correlation between WBV and BW, RBC, HGB, HCT, ALP, CHOL, TP, Globulin, Cl, Fibrinogen was presented.

• 유변학
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• 제2권2호
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• pp.19-27
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• 1990

레이저와 타이머장치를 설치한 낙구식 점도계에서 구와 니들이 주어진 구간을 통과 하는 시간을 측정하여 종말속도를 정확히 결정하였고 점성이 작은유체와 낮은 전단률 점성 과 영전단률 점성은 속이 빈 알루미늄 구와 니들이 이용하여 측정하였다. 알루미늄 구와 니 들의 속에 철분을 삽입하여 밀도를 다양하게 변화시켰다. 낙구식 점도계에서 측정한 낮은 전단률 점성과 영 전단률 점성 그리고 모세관점도계에서 측정한 높은전단률 점성과 무한 전 단률 점성을 이용하여 점탄성 유체의 특성이완시간을 결정하였다. 실린더 속의 시험용 유체 를 교란시키지 않고 밑면에 떨어진 구를 회수하는 장치를 설치하였다. 이 장치는 하나의 구 로써 점탄성유체의 특성확산시간을 측정하는데 대단히 효과적이었다. Polyacrylamide Separan AP-273 용액(농도 500-200 wppm)의 특성이안시간과 특성화산시간을 낙구식 점도 계와 모세관 점도계의 실험결과를 이용하여 결정하고 폴리며 용액의 퇴화 현상을 실험적으 로 분석하였다.

• 유변학
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• 제7권3호
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• pp.261-266
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• 1995

원관에서 power-law 유체에 대하여 수력학적 입구길이와 입구보정계수를 측정할수 있는 새로운 방법이 개발되었다. 유변학적 성질을 측정할수 있는 긴관과 입구보정계수를 측 정할수 있는 짧은 관을 가진 새로운 모세관 점도계를 이용하여 증류수를 실험한 결과 유변 학적 성질과 입구 보정계수가 표준값과 비교하여 1%안의 오차를 얻었다. Power-law 유체 에 대한 해석 및 실험결과(Carbopol 960 용액)도 이미 보고된 값과 $\pm$6% 이내로 잘 일치하 였다.

• International Journal of Vascular Biomedical Engineering
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• 제1권2호
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• pp.4-12
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• 2003

The present study investigated the effect of transverse vibration on the hemorheological characteristics of blood using a newly designed pressure-scanning capillary viscometer. As vibration was applied, aggregated blood cells (rouleaux) were disaggregated. The range of vibration frequency and amplitude are $0{\sim}100\;Hz$ and $0{\sim}0.8\;mm$, respectively for a capillary diameter 0.84 mm. As vibration increased, blood viscosity initially increased and tended to decrease. In order to delineate the unexpected results, the present study proposed two counteracting mechanisms of vibration related with red blood cell (RBC) aggregation affecting hemo-rheological properties. One is the reduction of RBC aggregation due to vibration causing an increase of blood viscosity. The other is forced cell migration due to the transverse vibration, which in turn forms a cell-free layer near the tube wall and causes a decrease of flow resistance.

• Journal of Pharmaceutical Investigation
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• 제5권3호
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• pp.43-49
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• 1975

The rheological properties of seven mixed sugar solutions of glucose, fructose, maltose, sucrose, and two kinds of honey, the chestnut and the acacia, were discussed. The fluidity of the above samples were studied by using the applied pressure horizontal viscometer with which glycerine was confirmed to be a Newtonian flow at $25^{\circ}C$. Time required to pass the constant volume of the sample fluids through the capillary was measured at various pressure differences, ${\Delta}p$, and the ${\Delta}p$ vs ${\Delta}p{\cdot}t$ in the Poiseuille equation was plotted. Shear rate against shearing stress, on the other hand, was plotted for the sample fluids and it was found that all the sample fluids have shown a Newtonian behavior. It was interesting to note that the shear viscosity increased as the concentration of sugar solutions increased, and as the concentration of sucrose became higher than that of maltose, although the total concentration of sugar solution is constant.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.61-64
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• 2000

In order to analyse the effect of the fluid viscosity changes on the centrifugal pump, the computer simulation method and the performance correction chart are used. The centrifugal pump is designed using the traditional method, and the 3D computational grid is generated for the impeller and casing. Working fluids are water, high viscous oil and muddy water. The viscosity of muddy water is measured by the unsteady capillary tube viscometer. The pump performances are predicted well through the computer simulation. The performance curves of head and efficiency for oil and muddy water are decreased. The torques of oil and muddy water, which is calculated by performance correction chart are predicted at a lower value than the computer simulation.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.295-301
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• 2005

Viscosity measurement standards were evaluated according to ISO/IEC 17025. The step-up procedure was employed to calibrate a series of capillary type master viscometers. Uncertainty was calculated with evaluation of various uncertainty factors affected in viscosity measurement. The maximum expanded uncertainty(U) of the master viscometer was $3.0{\times}10^{-3}$(at the confidence level of 95 %). This evaluation example will be useful in viscosity measurement uncertainty determination of other standard measurement.