A Highly Accurate and Consistent Microfluidic Viscometer for Continuous Blood Viscosity Measurement

Kang, Yang Jun,Yoon, Sang Youl,Lee, Kyeong‐,Hwan,Yang, Sung Blackwell Publishing Inc 2010 Artificial Organs Vol.34 No.11

<P><B>Abstract</B></P><P>A high‐precision microfluidic viscometer with a microfluidic channel array composed of 100 indicating channels is demonstrated in this study. The relative viscosity of the sample fluid could be measured by simply counting the number of the indicating channels occupied by the sample and the reference fluids. Using lumped parameter modeling, an analytical solution of the relative viscosity is derived. In order to evaluate the performance of the developed microfluidic viscometer, the viscosity values obtained by the microfluidic viscometer are compared with the ones obtained by a conventional viscometer. In Newtonian fluid (sodium dodecyl sulfate [SDS] solution) tests, the normalized differences in the viscosities measured by two methods are less than 2.5%. In non‐Newtonian fluid (whole blood, 45% hematocrit) tests at various shear rates, the viscosities measured by two methods are evaluated by a regression analysis via power law (<IMG src='/wiley-blackwell_img/equation/AOR_1078_mu1.gif' alt ='inline image'/>). The <I>k</I> values for both the microfluidic viscometer and the conventional viscometer are 12.953 and 13.175, respectively; the <I>n</I> values are 0.797 and 0.807, respectively. The normalized differences in two parameters measured by two methods are less than 2%. Thus, it could be concluded that the microfluidic viscometer developed in this study is capable of measuring viscosity of both Newtonian fluid (SDS solution) and non‐Newtonian fluid (whole blood) with a relatively high accuracy in a continuous and near real‐time fashion. Furthermore, the viscometer could be potentially employed in cardiopulmonary bypass procedures by continuously monitoring viscosity changes due to blood damages and hemodilution.</P>

A Novel Viscosity Measurement Technique Using a Falling Ball Viscometer with a High-speed Camera

Jo, Won-Jin,Pak, Bock-Choon,Lee, Dong-Hwan Korean Tribology Society 2007 KSTLE International Journal Vol.8 No.1

This study introduces a new approach to a falling ball viscometer by using a high speed motion camera to measure the viscosity of both Newtonian and non-Newtonian fluids from the velocity-time data. This method involves capturing continuous photographs of the entire falling motion of the ball as the ball accelerates from the rest to the terminal velocity state. The velocity of a falling ball was determined from the distance traversed by the ball by examining video tape frame by frame using the marked graduations on the surface of the cylinder. Each frame was pre-set at 0.01. Glycerin 74% was used for Newtonian solution, while aqueous solutions of Polyacrylamide and Carboxymethyl Cellulose were for non-Newtonian solutions. The experimental viscosity data were in good agreements with the results obtained from a rotating Brookfield viscometer.

A Novel Viscosity Measurement Technique Using a Falling Ball Viscometer with a High-speed Camera

Won Jin Jo,Bock Choon Pak,Dong Hwan Lee 한국트라이볼로지학회 2007 KSTLE International Journal Vol.8 No.1

This study introduces a new approach to a falling ball viscometer by using a high speed motion camera to measure the viscosity of both Newtonian and non-Newtonian fluids from the velocity-time data. This method involves capturing continuous photographs of the entire falling motion of the ball as the ball accelerates from the rest to the terminal velocity state. The velocity of a falling ball was determined from the distance traversed by the ball by examining video tape frame by frame using the marked graduations on the surface of the cylinder. Each frame was pre-set at 0.01. Glycerin 74% was used for Newtonian solution, while aqueous solutions of Polyacrylamide and Carboxymethyl Cellulose were for non-Newtonian solutions. The experimental viscosity data were in good agreements with the results obtained from a rotating Brookfield viscometer.

A novel viscosity measurement using a falling ball viscometer with a high-speed camera

Won Jin Jo(조원진),Bock Choon Pak(박복춘),Young I Cho(조영일) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

This study introduces a new approach to a falling ball viscometer by using a high speed motion camera to measure the viscosity of both Newtonian and non-Newtonian fluids from the velocity-time data. This method involves capturing continuous photographs of the entire falling motion of the ball as the ball accelerates from the rest to the terminal velocity state. Ball’s velocity was determined from the distance traversed by the ball by examining video tape frame by frame using the marked graduations on the surface of the falling ball cylinder. Each frame was pre-set at 0.01. Glycerin 74% was used for Newtonian solution, while aqueous solutions of Polyacrylamide and Carboxymethyl Cellulose were for non-Newtonian solutions. The experimental viscosity data were in good agreements with the results obtained from a rotating Brookfield viscometer.

Correction Method for High-Temperature Low-Viscosity Measurement System Using Narrow-Gap Rotational Viscometer

Sang-Hee Oh,Tae-Hyeong Kim,Sang Ho Lim,Jong-Yun Kim 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

Measurement of the physical properties of high-temperature molten salts is important for the efficient design and operation of molten salt reactors (MSR) in which the reactor coolant and nuclear fuel are in a homogeneous liquid state. Although some crucial physical properties such as viscosity, thermal conductivity, density, etc., have been drawing much attention, relative data, especially for molten chloride salts, are scarce. Thus, it is urgent to prepare the viscosity data as one of the key transport properties in thermal hydraulics analysis. However, it is not an easy task to measure the molten salt viscosity with high accuracy due to end effect, a small gap between the chamber and spindle, thermal expansion of the chamber and spindle at high temperatures in a rotational viscometer. Additionally, molten salt temperatures inside furnace are not uniform due to the large temperature gradient inside the chamber, and therefore the assumption of laminar condition can be violated. In this study, geometric factors, which can be a major interference in the torque measurement, were considered for the accurate determination of the viscosity. We established a high-temperature molten salt viscosity measurement system with Brookfield rotational viscometer. KNO3 molten salt was used as a model substance at a temperature range of 650–773 K. In-house designed spindles and chambers were made of corrosion-resistant alumina. Thermal expansion has a significant influence on the size and shape of the chamber and spindle. The effect of thermal expansion on the conventional correction method was examined with temperature variation and distribution. Gap size variation was also investigated in order to improve the accuracy.

회전식 점도계를 이용한 상업용 증점제의 점도 분석법 검토

반영란,정향연,윤소정,박현진,홍성준,조성민,이양봉,신의철 한국식품과학회 2024 한국식품과학회지 Vol.56 No.1

In this study, the viscosity of six food additives used as thickeners (xanthan gum, glucomannan, guar gum, pullulan, locust bean gum, and polyvinyl alcohol) was verified using a Brookfield rotational viscometer. Pullulan was prepared in a 10% aqueous solution, and other samples were prepared in a 1% aqueous solution. The measurements showed that glucomannan had a high viscosity value of >3,000.00 cp, compared to guar gum with >2,500.00 cp and xanthan gum with >1,000.00 cp. Locust bean gum and pullulan had low viscosity values of 110.00 cp and polyvinyl alcohol had low viscosity values of 6.60 cp. All samples were subjected to intra-day and inter-day precision analyses. As a result of cross-validation performed by the institution, similar viscosity values were achieved for each sample. Therefore, this data show that the rotary viscometer can contribute to high precision when measuring viscosity.

불균일 성질을 평가하기 위한 분획화된 galactomannan의 이화학적 특성

김경이(Kyeong-Yee Kim),이은경(Eun-Kyung Lee) 한국식품과학회 2013 한국식품과학회지 Vol.45 No.4

Mannose 기본구조에 galactose 치환체 비율이 4:1인 화학적 구조와 평균 분자량이 1,050 kg/mol인 LBG를 황산암모늄 침전법을 사용하여 분자량 크기별로 분획하여 분획물질들 간에 서로 다른 물리화학적 성질을 확인하였다. 황산암모늄을 맑은 용액에 천천히 첨가한 후 얻어진 침전물을 원심분리에 의해 모집, 탈이온수에 대한 투석 후 동결상태에서 건조시켜서 첫 번째 분획물을 얻었고 동일한 방법으로 각 단계별 분획물을 여섯 단계 까지 얻었다(F1-F6). 수득율은 F1 7.1% 부터 F6 6.35%까지 총 65%였다. 각 분획물들의 묽은 농도범위 0.05 g/dL 이하에서 Ubbelohde viscometer로 흐르는 시간을 측정하여 상대점성도, 비점성도, 유도점성도 및 본성점성도를 구하였으며 그 값은 F1:8.44, F2:4.59,F3:9.89, F4:8.80, F5:8.30, F6:8.10 dL/g이었다. F1과 F2 분획물이 갖는 본성 점성도 값은 기대치보다 작았고 그 원인은 단백질 성분을 포함하는 것으로 판단되어 함량을 측정한 결과 전체 단백질 함량 3.45%중에 F1, F2가 2.59%를 포함하고 있음을 확인하였다. 또한 고분자 물질의 용질-용매간의 상호작용과 응집상태에 의존하는 상태를 나타내는 k (Hugg. Coeff.)값을 측정한 결과 값의 범위는 0.463-0.781이였고 점성도 값이 클수록 k값이 커지는 경향을 나타내었다. 분획물들의 체류용량에 대한 RI detector 크로마토그램은 4개의 분획물들의 다당류는 6.0에서 9.0 mL에서 용리되었고 염 혹은 oligomeric sugar 성분은 10에서 11 mL에서 용리되었음을 나타내었다. 중량 평균 분자량, 수 평균 분자량, 회전반경 및 본성 점성도 값들은 cp= 0.5 mg/mL, dn/dc = 0.145의 RI 피크면적에 기초를 둔 OmniSEC 프로그램으로 계산되었다. 본성 점성도 값은 F3: 10.15, F4: 9.99, F5: 9.35, F6: 9.31이었고 Mw값 범위는 617-674 kg/mol, Mn값 범위는 324-423%, recovery 72.44-101.61%였다. Ubbelohde viscometer와 SEC로 측정한 각 분획물들의 본성 점성도 값을 비교한 결과, 측정에 사용한 기기 원리와 계산식의 영향으로 수치에는 미소한 차이가 있었으나 분획물 순서대로 본성점성도가 감소하는 경향은 동일하여 황산암모늄 침전법에 의한 LBG 분획화가 차별화 있게 잘 이루어졌음을 확인하였다. 화학물질에 대한 안정제 및 식품첨가제로 주로 사용되고 있는 LBG 복합물질을 단순물질로 분획화하여 균일한 성분의 물리화학적 성질을 연구한 것은 안정제 및 첨가제의 효과를 높이고 사용범위가 확대될 수 있을 것으로 기대된다. Heterogenous samples of locust bean gum (galactomannan) were prepared into homogeneous substances. Locust bean gum was fractioned using ammonium sulfate (14.11-23.08%, w/w). The intrinsic viscosity was obtained by extrapolating reduced viscosity versus concentration by using an Ubbelohde viscometer. The ranges of intrinsic viscosity for fractions that not included protein (F3-F6) and fractions that included protein (F1-F2) were 9.89-8.10 and 8.44-4.59, respectively. Values for Huggins coefficient (k), which depends on physical interactions, were 0.46-0.78. Increasing ammonium sulfate concentration was associated with a weak trend towards lower molecular weight and intrinsic viscosity by size-exclusion chromatography (SEC): Mw ranged from 674 to 617 kg/mol and [η] from 9.80 to 8.10 dL/g between F3 and F6. The evaluations of those fractions by using SEC and the Ubbelohde viscometer produced very similar values, as predicted. We verified the application of a gradient of ammonium sulfate to precipitate locust bean gum into fractions of different molecular size and show structural variations.

Rheometer와 Viscometer를 이용한 SAC305 솔더페이스트의 측정 방법에 따른 점도 비교

박정빈,정명근,나승렬,조용석,김윤찬,김지훈,강남현 대한용접·접합학회 2023 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2023 No.10

점도 모니터링에 의한 식물유의 바이오디젤화

현영진 제주대학교 공과대학 첨단기술연구소 2007 尖端技術硏究所論文集 Vol.18 No.-

The transesterification of vegetable oils such as canola oil, soybean oil and corn oil with the amount of catalyst and molar ratio of methanol to oil was performed at 60℃ and lOOOs^(-1) of shear rate on the rotary viscometer. The viscosity of fatty acid methyl ester at different temperature was estimated by Orrick and Erbar's model, he overall yield was predicted through monitoring the viscosity of fatty acid methyl esters. The overall yield at the 1:6 molar ratio and 0.6wt% NaOH for vegetable oils showed 85 - 95% for 6.1 - 6.8mm^(2)/s of viscosity in 25 minutes and was predicted well by the relation of viscosity (n_(mix)) monitored.

낙구식 점도계를 이용한 아이스슬러리의 점도측정에 관한 연구

김명준,유직수,임재근,최순열 대한설비공학회 2007 설비공학 논문집 Vol.19 No.8

The present study has dealt with the measuring method of ice slurry viscosity using falling sphere viscometer. The experimental apparatus was composed by test section and high-speed video system. And the spheres used in this study were alumina and glass. The main parameters were ice packing factor (IPF) and falling velocity of sphere so the acquired results were discussed for these parameters. The viscosity of ice slurry was calculated by using measured falling velocity and moving distance at instantaneous time and the Stokes hypothesis was used for this calculation. It was clarified that possible measuring range was IPF=0.06~0.14 of this type of measuring device and measuring method. In addition, it was clarified that the viscosity of ice slurry increased to increase of ice packing factor (IPF) of ice slurry