• Title/Summary/Keyword: relative viscosity

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The Relationship between Viscosity of Soluble Dietary Fiber and their Hypoglycemic Effects (수용성 식이섬유소의 점도가 혈당강하에 미치는 영향)

  • 김은희
    • Journal of Nutrition and Health
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    • v.29 no.6
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    • pp.615-621
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    • 1996
  • Experiments were carried out in humans to assess the relationship between viscosity and post-prandial glucose response of soluble fibers. Eight(3 male and 5 female) healthy individuals were tested for their glucose response after taking control meals or 3 test fiber meals of different viscosities. Meal viscosity of the test food was adjusted to be between 200 and 70, 000 cps. There was a significant increase in post-prandial glucose response(p=0.01) in control meals by solely increasing the volume of water. Fiber with the highest viscosity konjac mannan demonstrated the lowest relative glucose response(70.1$\pm$6.6), followed by medium viscosity xanthan (79.3$\pm$8.7)and low viscosity psyllium (86.3$\pm$10.5). The difference is significant at the level of p<0.05. However, no significant difference in relative glucose response of the same fiber was found when the 4 levels of water were added to make different meal viscosity of each fiber (p=0.476). This result suggested that hypoglycemic action of soluble dietary fibers is related to fiber viscosity rather than meal viscosity.

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Prediction of Viscosity in Liquid Epoxy Resin Mixed with Micro/Nano Hybrid Silica (액상 에폭시 수지와 마이크로/나노 하이브리드 실리카 혼합물의 점도 예측)

  • Huang, Guang-Chun;Lee, Chung-Hee;Lee, Jong-Keun
    • Korean Journal of Materials Research
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    • v.21 no.2
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    • pp.100-105
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    • 2011
  • The relative viscosity was measured at different filler loadings for a cycloaliphatic epoxy resin and hexahydro-4-methylphthalic anhydride hardener system filled with micro/nano hybrid silica. Various empirical models were fitted to the experimental data and a fitting parameter such as critical filler fractions (${\phi}_{max}$) was estimated. Among the models, the Zhang-Evans model gave the best fit to the viscosity data. For all the silica loadings used, ln (relative viscosity) varied linearly with filler loadings. Using the Zhang-Evans model and the linearity characteristics of the viscosity change, simple methods to predict the relative viscosity below ${\phi}_{max}$ are presented in this work. The predicted viscosity values from the two methods at hybrid silica fractions of $\phi$ = 0.086 and 0.1506 were confirmed for a micro:nano = 1:1 hybrid filler. As a result, the difference between measured and predicted values was less than 11%, indicating that the proposed predicting methods are in good agreement with the experiment.

Relative Viscosity of Emulsions in Simple Shear Flow: Temperature, Shear Rate, and Interfacial Tension Dependence (전단유동에서 온도, 전단속도, 계면장력 변화에 따른 에멀전의 유변학적 특성)

  • Choi, Se Bin;Lee, Joon Sang
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.8
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    • pp.677-682
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    • 2015
  • We simulate an emulsion system under simple shear rates to analyze its rheological characteristics using the lattice Boltzmann method (LBM). We calculate the relative viscosity of an emulsion under a simple shear flow along with changes in temperature, shear rate, and surfactant concentration. The relative viscosity of emulsions decreased with an increase in temperature. We observed the shear-thinning phenomena, which is responsible for the inverse proportion between the shear rate and viscosity. An increase in the interfacial tension caused a decrease in the relative viscosity of the decane-in-water emulsion because the increased deformation caused by the decreased interfacial tension significantly influenced the wall shear stress.

Solution Viscosity and Relative Reactivity of Branched and Linear Polycarbonates

  • Kim, Sang-Pil;Lee, Bong-Hee;Kim, Sang-Hern;Kim, Whan-Gi
    • Journal of the Korean Applied Science and Technology
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    • v.17 no.2
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    • pp.76-82
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    • 2000
  • The relative reactivities of branched and linear polycarbonates were investigated by measuring unreacted chloroformate concentration. It was found that the polymerization for the branched polymer proceeded ca. 10 times faster than that for the linear polymers. The effect of catalyst on a condensation step was studied by changing the amount of TEA (triethylamine) at $t_{0}$ and $t_{60}$ with keeping constant amount of TEA. The viscosity average molecular weight for the obtained branched polycarbonates were measured and compared with those of linear polycarbonates. It was found that the viscosity molecular weights of the obtained polymers decreased nonlinearly as wt % of added oligomer increased. The solution viscosities in methylenechloride for linear and branched polycarbonate increased nonlinearly as the content of polymer increased.

An experimental study and new correlations of viscosity of ethylene glycol-water based nanofluid at various temperatures and different solid concentrations

  • Bidgoli, Mahmood Rabani;Kolahchi, Reza;Karimi, Mohammad Saeed
    • Structural Engineering and Mechanics
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    • v.58 no.1
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    • pp.93-102
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    • 2016
  • This article presents an experimental study on the effect of temperature and solid volume fraction of nanoparticles on the dynamic viscosity for the CuO/EG-water nanofluid. Nanoparticles with diameter of 40 nm are used in the present study to prepare nanofluid by two-step method. A "Brookfield viscometer" has been used to measure the dynamic viscosity of nanofluid with solid volume fraction up to 2% at the temperature range between 20 to $60^{\circ}C$. The findings have shown that dynamic viscosity of nanofluid increases with increasing particle volume fraction and decreasing temperature. Nine different correlations are developed on experimental data point to predict the relative dynamic viscosity of nanofluid at different temperatures. To make sure of accuracy of the proposed correlations, margin of deviation is presented at the end of this study. The results show excellent agreement between experimental data and those obtained through the correlations.

A Study on the Drying Shrinkage and Carbonation High Flowing Concrete using Viscosity Agent (증점제를 사용한 고유동콘크리트의 건조수축 및 중성화에 관한 연구)

  • Kwon, Young-Jin
    • Journal of the Korea Institute of Building Construction
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    • v.3 no.3
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    • pp.121-126
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    • 2003
  • This study investigated about several mix factors came up to drying shrinkage and carbonation of high flowing concrete using viscosity. The results are as follows; Drying shrinkage ratio of high flowing concrete using viscosity showed higher for early age, but lower than normal concrete as long age. Also, drying shrinkage ratio and reduction ratio of mass showed higher and relative dynamic modulus of elasticty showed lower as W/C was higher generally. And in case of high flowing concrete using viscosity, carbonation wasn't confirmed without the kinds of cement and viscosity except 50C.

A Study on the Viscous Properties of Polyvinyl Acetate Emulsion Mixed with SBR, Polyurethane and Epoxy Latex (SBR, 폴리우레탄 및 에폭시 라텍스를 혼합한 폴리초산비닐 에멀젼 수지의 점성에 관한 연구)

  • Choi, Sang-Goo;Suh, Won-Dong;Park, In-Suk
    • Elastomers and Composites
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    • v.33 no.2
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    • pp.83-92
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    • 1998
  • SBR latex, polyurethane latex and epoxy latex were mixed with polyvinyl acetate emulsion in 0~15% (wt.%). For the mixtures, the viscous properties were examined. The viscosity was influenced by the dispersed phase and the chain structures of polymer, and decreased with the rising of temperatures. The viscosity was increased with mixing of epoxy latex, but decreased with addition of SBR latex or polyurethane latex. Thixotropic index was influenced on the size of micelle and hydrogen bond. The thixotropic index was increased with mixing of epoxy latex or polyurethane latex within 5%, but keep up equality over that. The thixotropic index was decreased with mixing of SBR latex within 5%, but keep up equality over that. The relative viscosity were influenced on the activity of molecule and the interference of dispersed phases, was increased with the rising of temperatures. The relative viscosity was decreased with mixing of epoxy latex, but increased with mixing of SBR latex or polyurethane latex.

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A phenomenological approach to suspensions with viscoelastic matrices

  • Tanner Roger I.;Qi Fuzhong
    • Korea-Australia Rheology Journal
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    • v.17 no.4
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    • pp.149-156
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    • 2005
  • A simple constitutive model for viscoelastic suspensions is discussed in this paper. The model can be used to predict the rheological properties (relative viscosity and all stresses) for viscoelastic suspensions in shear and elongational flow, and the constitutive equations combine a 'viscoelastic' behaviour component and a 'Newtonian' behaviour component. As expected, the model gives a prediction of positive first normal stress difference and negative second normal stress difference; the dimensionless first normal stress difference strongly depends on the shear rate and decreases with the volume fraction of solid phase, but the dimensionless second normal stress difference (in magnitude) is nearly independent of the shear rate and increases with the volume fraction. The relative viscosities and all the stresses have been tested against available experimental measurements.

The rate and extent of acid indued coagulation of milk protein and physical characteristics of resultant coagulum (산에 의한 응고화에 영향을 미치는 인자들과 형성된 응고물의 물리학적 특징)

  • Bae, Hyuk-Jin;Kim, Byung-Yong;Kim, Myung-Hwan
    • Applied Biological Chemistry
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    • v.35 no.2
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    • pp.69-75
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    • 1992
  • Viscosity changes of acidified milk at the various pH $ranges(5.2{\sim}4.2)$was measured as a function of temperature. The rate and extent of acid-induced coagulation of milk protein were monitored by turbidity changes as a function of temperature, preheating and salt. Relative viscosities of acidified milk were also measured. The coagulation of casein occurred in a specific pH range and was accompanied by a sharp increase in viscosity at pH of $5.0{\sim}5.2$, depending on the heating temperatures. Onset pH of coagulation and maximum coagulation rate were enhanced by increasing temperatures and preheating process and reduced by addition of salt. Relative viscosity of acidified milk was reversed at the same conditions, reflecting the size of casein coagulum formed was related to the coagulation rate.

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Preliminary Study on the Relationship between Viscosity of Paste and Flowability of Mortar (페이스트 점도에 의한 모르타르 유동 특성에 관한 기초 연구)

  • Kim, Seung Hyun;Park, Chung-Hoon;Kim, Baek-Joong;Yi, Chong-Ku;Kang, Kyung-In
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.269-270
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    • 2012
  • In this study, for purpose of having a prediction on the flowability of mortar, we use the theory of excess paste, which gives a relationship between viscosity of paste versus water-binder ratio and mortar flow versus relative excess paste volume. Pastes and Mortars with four different mix proportions incorporating mineral admixtures were prepared. As a result of experiment, it seems that high flowability of mortar can be attributed to both lower viscosity of paste and increasing the volume of excess paste.

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