• Title/Summary/Keyword: Consistency index

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An experimental study on the viscosity of visco-elastic fluids (점탄성유체의 점성에 관한 실험적 연구)

  • 김춘식;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.6 no.2
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    • pp.21-41
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    • 1982
  • Viscosity, especially characteristic among various properties of visco-elastic fluids such as high polymer solutions, is affected mainly by temperature and concentration. Hence, it is important for fluid engineering to express, by some equations, how the fluid characteristics vary with the change of temperature and concentration and to analyze them to obtain consistent viscous characteristics. High polymer solutions, synthetic products of modern chemical industry, suggest many interesting investigations because they are typical visco-elastic materials. Experimentation was made to derive some useful fluid characteristic equations of SEPARAN-NP10 (polyacylamide) expressed by n (flow behavior index) and K' (consistency index) when it is given temperature and concentration variation. To measure viscosity, capillary viscometer was adopted and the range of experimentation is 0-2,000 P.P.M. in concentration and 15-55 .deg.C in temperature. The experimental results are summarized as follows: The flow behavior index n 1) has nearly constant results irrespective of temperature variation at same conentration and the results are shown in (Table. 4-4-3) 2) has following equation, regardless of temperature, for the variation of concentration. n=-1.0765*10$^{-4}$ P+0.9915 (P:P.P.M.) The consistency index K' 1) has different results for the variation of temperature at same concentration and the results are given in (Table.4-7-2) 2) has following equation for the variation of concentration at same temperature. log 10$^{4}$K' =6.4785*10$^{-4}$ P-1.0529 (P:P.P.M)

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A Study on the Model Improvement of Korean Industrial Standards-Quality Excellence Index(KS-QEI) (KS제품 품질우수성지수 모델 개선 방안에 관한 연구)

  • Kim, Tai-Kyoo;Kim, Myung Joon
    • Journal of Korean Society for Quality Management
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    • v.41 no.3
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    • pp.327-335
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    • 2013
  • Purpose: The purpose of this study is to suggest the modified 'Korean Standard-Quality Excellence Index' model and analyze the improvement effect with survey data by comparing the properness between current and suggested model result. Methods: The collected data through the survey were analyzed using paired t-test and unbalanced ANOVA method for testing the consistency of two customer satisfaction evaluating categories and comparing the current model to suggested model for confirming the improvement of performance. Results: The statistical analysis result shows that adjusted model using prior information improves the consistency between two customer satisfaction in case of short life-cycle product. Also long life-cycle product case, the result shows difference gap decreasing with same direction. Conclusion: Considering statistical model for QEI reflecting the characteristic of product group such as life cycle seems to be meaningful. Since index may be compared yearly base for checking the trend, careful approaching without big change should be considered for application.

Emulsion stability of cosmetic creams based on water-in-oil high internal phase emulsions

  • Park, Chan-Ik;Cho, Wan-Gu;Lee, Seong-Jae
    • Korea-Australia Rheology Journal
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    • v.15 no.3
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    • pp.125-130
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    • 2003
  • The emulsion stability of cosmetic creams based on the water-in-oil (W/O) high internal phase emulsions (HIPEs) containing water, squalane oil and cetyl dimethicone copolyol was investigated with various compositional changes, such as electrolyte concentration, oil polarity and water phase volume fraction. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The slope change of complex modulus versus water phase volume fraction monitored in the linear viscoelastic region could be explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsions: the greater the increase of complex modulus was, the more the coalescence occurred and the less consistent the emulsions were. Emulsion stability was dependent on the addition of electrolyte to the water phase. Increasing the electrolyte concentration increased the refractive index of the water phase, and thus decreased the refractive index difference between oil and water phases. This decreased the attractive force between water droplets, which resulted in reducing the coalescence of droplets and increasing the stability of emulsions. Increasing the oil polarity tended to increase emulsion consistency, but did not show clear difference in cream hardness among the emulsions.

Internal Consistency and Concurrent Validity of Korean Language Version of WHODAS 2.0: 12 Item-Self Administered

  • Lee, Hae-Jung;Kim, Da-Jeong
    • The Journal of Korean Physical Therapy
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    • v.23 no.6
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    • pp.23-29
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    • 2011
  • Purpose: The aim of this study was to validate the Korean version of World Health Organization Disability Assessment Schedule 2.0 (KWHODAS 2.0) in 12 item-self administered version (12-self). Methods: The KWHODAS 2.0 and Korean Functional Rating index (KFRI) were tested for internal consistency, ceiling and floor effects, and concurrent validity in 111 patients with low back pain and/or neck pain. Results: A very high level of internal consistency was shown for both instruments; ${\alpha}$=0.96 with KWHODAS 2.0; 12-self and ${\alpha}$=0.97 for KFRI. No ceiling and/or floor effects were found in both the instruments. The KWHODAS 2.0 and KFRI were highly correlated (r=0.77), and the relationship of each item between KWHODAS 2.0 and KFRI was ranging from r=0.09 to 0.72. Conclusion: We conclude that the KWHODAS 2.0: 12-self and KFRI are reliable and are valid instruments for the measurement of disability in Korean speaking patients with low back and/or neck pain. Both instruments, the KWHODAS 2.0; 12-Self and KFRI are now suitable for use in clinical practice and research applications.

Gelatinization Properties of Pigmented Rice Varieties (유색미의 품종별 호화 특성)

  • Ha, Tae-Youl;Park, Sung-Hee;Lee, Sang-Hyo;Kim, Dong-Chul
    • Korean Journal of Food Science and Technology
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    • v.31 no.2
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    • pp.564-567
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    • 1999
  • Gelatinization characteristics of pigmented rice varieties were determined in terms of amylose contents, amylograph, gel consistency, water absorption index (WAI) and water soluble index (WSI). Amylose contents of black and red rice were lower than those of brown rice, especially Sanghaehyanghyulla exhibited the lowest amylose contents among the pigmented rice varieties tested. There was no significant difference in WAI among the pigmented rice varieties, but WSI was lower in red rice than the others. Peak viscosity of black rice measured in a Brabender amylograph was lower than those of red and brown rice.

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Prediction of Sensory Properties for the Stirred-type Fruit Yogurts by Instrumental Measurements (기계적 측정에 의한 호상요구르트의 관능특성 예측)

  • Oh, Se-Jong;Sim, Jae-Hun;Hur, Jae-Kwan;Shin, Jung-Gul;Kim, Sang-Kyo;Baek, Young-Jin
    • Korean Journal of Food Science and Technology
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    • v.25 no.6
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    • pp.620-625
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    • 1993
  • This experiment was carried out to predict the sensory properties of yogurt by instrumental methodology. Sensory attributes such as viscosity, mouth-feel, taste and quality were investigated. Instrumental parameters were measured with refractometer, viscometer, consistometer and rheometer. Sensory data showed that viscosity of peach yogurt was higher than that of strawberry and tropical-fruit-mixed (TFM) yogurts (p<.05). All instrumental parameters of peach yogurt were higher than those of strawberry and TFM yogurts, except cohesiveness and elasticity (p<.05). Viscosity measured by panelists was significantly correlated with instrumental viscosity, consistency, hardness, adhesiveness and gumminess in the fruit yogurts (p<.05). But mouth-feel and quality of yogurts showed poor relationships with instrumental parameters. The effective instrumental parameters for predicting sensory viscosity ($Y_{1}$) of yogurts were consistency ($X_{1}$), viscosity ($X_{2}$) and cohesiveness ($X_{3}$). And those for predicting mouth-feel ($Y_{2}$) were consistency. The estimated regression equations were as follows; $Y_{1}=4.968-0.0486X_{1}+0.00012X_{2}+0.0348X_{3},\;Y_{2}=5.701+0.0154X_{1}$.

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Development of Drought Index based on Streamflow for Monitoring Hydrological Drought (수문학적 가뭄감시를 위한 하천유량 기반 가뭄지수 개발)

  • Yoo, Jiyoung;Kim, Tae-Woong;Kim, Jeong-Yup;Moon, Jang-Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.4
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    • pp.669-680
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    • 2017
  • This study evaluated the consistency of the standard flow to forecast low-flow based on various drought indices. The data used in this study were streamflow data at the Gurye2 station located in the Seomjin River and the Angang station located in the Hyeongsan River, as well as rainfall data of nearby weather stations (Namwon and Pohang). Using streamflow data, the streamflow accumulation drought index (SADI) was developed in this study to represent the hydrological drought condition. For SADI calculations, the threshold of drought was determined by a Change-Point analysis of the flow pattern and a reduction factor was estimated based on the kernel density function. Standardized runoff index (SRI) and standardized precipitation index (SPI) were also calculated to compared with the SADI. SRI and SPI were calculated for the 30-, 90-, 180-, and 270-day period and then an ROC curve analysis was performed to determine the appropriate time-period which has the highest consistency with the standard flow. The result of ROC curve analysis indicated that for the Seomjin River-Gurye2 station SADI_C3, SRI30, SADI_C1, SADI_C2, and SPI90 were confirmed in oder of having high consistency with standard flow under the attention stage and for the Hyeongsan River-Angang station, SADI_C3, SADI_C1, SPI270, SRI30, and SADI_C2 have order of high consistency with standard flow under the attention stage.

Stability of High Internal Phase Emulsions

  • Park, C.I.;Cho, W.G.
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.25 no.4 s.34
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    • pp.65-74
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    • 1999
  • We have studied the stability of W/O high internal phase emulsions(HIPE) containing water, cetyl dimethicone copolyol and oils varying magnesium sulfate in the range 0 to 0.5 wt% and oil polarities, respectively. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of complex modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. The increasing pattern of complex modulus versus volume fraction has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion. The stability is dependent on: (i) the choice of the oil is important, the requirements coincide with the requirements for the formation of the rigid liquid crystalline phases; and (ii) addition of salts the aqueous phase opposes the instability due to coalescence. Increasing the salt concentration increases the refractive index of the aqueous phase. It lowers the difference in the refractive index between the oil and aqueous phases. This decreases the attraction between the water domains, thus increasing the stability.

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Rheological Properties of Cowpea and Mung Bean starch Gels and Pastes (동부와 녹두전분 Gel 및 Paste의 Rheological Properties)

  • 손경희
    • Journal of the Korean Home Economics Association
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    • v.26 no.3
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    • pp.93-102
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    • 1988
  • Rheological properties of cowpea and mung bean starch gels and pastes were investigated and compared with Instron Universal Testing machine and Brabender Viscometer. As the result of puncture test of gels, yield point force of mung bean starch gel was higher than that of cowpea starch gel. Compression coefficient of cowpea starch gel calculated by Bourne's equation was lower than that of mung bean starch gel. the stress relaxation test showed that viscoelastic properties of cowpea and mung bean starch gels may be represented by six element Maxwell model consisting of three Maxwell element in parallel. Cowpea and mung bean starch pastes showed bingham pseudoplastic behavior in 3, 5, 6, 7 and 8%. The consistency index in 7∼8% of cowpea starch paste were lower than those of mung bean starch paste. concentration dependence on consistency index and yield stress in mung bean starch were higher than those of cowpea starch. The yield stress of starch pastes was significantly correlated with yield point force by puncture test (r=0.996).

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Stability of High Internal Phase Emulsions

  • Park, C-I.;W-G. Cho
    • Proceedings of the SCSK Conference
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    • 1999.10a
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    • pp.65-74
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    • 1999
  • We have studied the stability of W/O high internal phase emulsions(HIPE) containing water, cetyl dimethicone copolyol and oils varying magnesium sulfate in the range 0 to 0.5wt% and oil polarities, respectively. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of concentrated modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. The increasing pattern of complex modulus versus volume fraction has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion. The stability is dependent on: (i) the choice of the oil is important, the requirements coincide with the requirements for the formation of the rigid liquid crystalline phases :5; and (ii) addition of salts the aqueous phase opposes the instability due to coalescence:. Increasing the salt concentration increases the refractive index of the aqueous phase. It lowers the difference in the refractive index between the oil and aqueous phases. This decreases the attraction between the water domains, thus increasing the stability.

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