• Tribology and Lubricants
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• v.14 no.1
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• pp.85-93
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• 1998

The Bair & Winer's limiting shear stress rheological model is incorporated into the Reynolds equation to successfully predict the traction and film thickness for an isothermal line contact using the primary rheological properties. The modified WLF viscosity model and Barus viscosity model are also adapted for the realistic prediction of EHD tractional behavior. The influences of the limiting shear stress and slide-roll ratio on the pressure spike, film thickness, distribution of shear stress and nonlinear variation of traction are examined. A good agreement between the disc machine experiments and numerical traction prediction has been established. The film thickness due to non-Newtonian effects does not deviate significantly from the fdm thicknesss with Newtonian lubricant.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.188-194
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• 1999

Fiber reinforced composite materials are widely used in automotive industry to produce parts that are large, thin. lightweight. strong and stiff. It is very important to know a charge shape in order to have good products in the compression molding. In particular, the product such as a bumper beam is composed of the random and unidirectional fiber mats. This study analyzes numerically the characteristics of flow fronts such as a bulging phenomenon made by changing viscosity of random mat and unidirectional fiber mat and slip parameters. And it is discussed that the effect of ratio of viscosity A and stack type on mold filling parameters

• Geomechanics and Engineering
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• v.33 no.2
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• pp.211-219
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• 2023

This study analyzes the changes in the physical properties of grout by irradiating it with ultrasonic energy and assesses the injectability of the grout into deep rock fractures. The materials used in the research are OPC (Ordinary Portland Cement) and MC (Micro Cement), and are irradiated depending on the water/cement ratio. After irradiating the grout with ultrasonic energy, viscosity, compressive strength, and particle size are analyzed, and the results of the particle size analysis were applied to Nick Barton's theory to evaluate the injectability of the grout into deep rock fractures under those conditions. It was found that the viscosity of the grout decreased after ultrasonic wave irradiation, and the rate of viscosity reduction tended to decrease as the water/cement ratio increased. Additionally, an increase in compressive strength and a decrease in particle size were observed, indicating that the grout irradiated with ultrasonic energy was more effective for injection into rock fractures.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.147-154
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• 2004

It is the aim of this study to propose the fundamental data for the establishment of the application and qualify standard of the mixed type superplasticizer after investigating and comparing the fluidity of high flowing concrete according to the component ratio of superplasticizer such as naphthalene sulfonated and melamine sulfonated. The results of this study were shown as the followings; 1) The fluidity and adsorption ratio of cement-paste were improved according to the increasing of naphthalene sulfonated component ratio, and apparent viscosity of cement-paste was improved according to the Increasing of melamine sulfonated component ratio. 2) In case of using the granulated blast-furnace slag, the fluidity of cement-paste was considerably good and the adsorption ratio was decreased and in case of using fly-ash, the apparent viscosity and adsorption ratio of cement-paste were improved. 3) The dispersive capacity performance of concrete can be improved by means of the increasing of naphthalene sulfonated component ratio. Also the viscosity and early strength can be improved by means of the increasing of melamine sulfonated component ratio.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.293-297
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• 1999

Direct comparisons are made between curvature-corrected eddy viscosity models and the present experimental data. The results show that the curvature effects can be quantified through a curvature parameter R$\sub$c/ or S$\sub$c/ and a non-equilibrium value of p/$\varepsilon$. The data reveal a significant dependence of the eddy viscosity on the curvature and strain history for a fluid in a stabilizing curvature field, S$\sub$c/>1.0. Especially, experimental result shows that the eddy viscosity coefficient ratio at S$\sub$c/=3 changes from 10 to -10 although shear rate preserved constant. It is therefore suggested that proper curvature modifications, particularly the strain history effect, must be introduced into current eddy viscosity models for their application to turbulent flows subjected to curvature straining field for a non-negligible period of time.

• Journal of ILASS-Korea
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• v.14 no.3
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• pp.122-130
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• 2009

Vegetable oil and its derivatives as an alternative diesel fuel have become more attractive recently because of its environmental benefits and the fact that they are made from renewable resources. Viscosity is the most significant property to affect the utilization of vegetable oil and its derivatives in the compression ignition engines. This paper presents the existing correlations for predicting the viscosity of vegetable oil and its derivatives for compression ignition engines. According to the parameter considered in the correlations, the empirical correlations can be divided into six groups: correlations as a function of temperature, of proportion, of composition, of temperature and composition, of temperature and proportion, and of fuel properties. Out of physical properties of fuel, there exist in the literature several parameters for giving the influence on kinematic viscosity such as density, specific gravity, the ratio of iodine value over the saponification value, higher heating value, flash point and pressure. The study for the verification of applicability of existing correlations to non-edible vegetable oil and its derivatives is required.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.5
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• pp.582-590
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• 2005

The application of consomme prepared with different ratios of ground beef and ground chicken to improve taste preferences and the cost of foodstuffs was attempted by reviewing fundamental data and the effect on the sensory and physical characteristics of treatment These treatments were prepared with different ratios(9:1(A), 7:3(B), 5:5(C), 3:7(D), 1:9(E) w/w) of ground beef and ground chicken, respectively. Sensory properties were evaluated in the aspects of both acceptability and intensity. From the acceptability aspect, A treatment showed the highest scores in smell, B in mouthfeel and taste, A and B in color and overall acceptability, respectively. In terms of acceptability, B treatment was favored most for color, mouthfeel, taste and overall acceptability except smell. The more the ground chicken, the higher the intensity aspect E treatment showed higher values than A in all the intensity aspects. Moisture contents and crude proteins increased by increasing the mixed ratio of ground beef, whereas crude ash, solid matter and pH increased by increasing the mixed ratio of ground chicken. Tumidity values were the highest in E treatment, whereas the lowest in A. Tumidity values were increased significantly by increasing the mixed ratio of ground chicken. Viscosity increased by increasing the mixed ratio of ground chicken. The highest viscosity was shown in E treatment The colorimetric lightness values(L) decreased and redness(a), yellowness(b) and total color difference values(AE) increased significantly by increasing the mixed ratio of ground chicken. This experimental study showed that A and B treatment had the highest values in overall acceptability. The results of analysis in crude protein, solid matter, tumidity and viscosity were increased by increasing the mixed ratio of ground chicken. B treatment prepared with a ratio of 7:3 of ground beef and chicken had the most favorable sensory quality. These results suggested the basic information to improve acceptability and to save the costs of Consomme recipes for foodservice institutions.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.295-304
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• 2001

This study was conducted to investigate the cooking properties of noodles made from composite flour blended with green tea powder. As the ratio of green tea powder increased, development time was longer than that of the control. The stability of dough showed higher value than the control except 2% addition group. The highest viscosity was at the 4% addition group. but 2% addition group showed the lowest viscosity. As the additional ratio of green tea powder was increased. the volume expansion ratio was increased, but water soluble solid matters contents in all addition groups had a lower level than that of the control. Also, the yellowness level of noodle was increased, but the brightness, redness and color and flavor acceptability was decreased, as the additional ratio was increased. However. 2~4% addition group of green tea powder had a similar acceptability profile to that of the control group.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.67-75
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• 2007

As a part of abating the formaldehyde emission of urea-formaldehyde (UF) resin adhesive by lowering formaldehyde to urea (F/U) mole ratio, this study was conducted to investigate properties of UF resin adhesive with different F/U mole ratios. UF resin adhesives were synthesized at different F/U mole ratios of 1.6, 1.4, 1.2, and 1.0. Properties of UF resin adhesives measured were non-volatile solids content, pH level, viscosity, water tolerance, specific gravity, gel time and free formaldehyde content. In addition, a linear relationship between non-volatile solids content and sucrose concentration measured by a refractometer was established for a faster determination of the non-volatile solids content of UF resin. As F/U mole ratio was lowered, non-volatile solids content, pH, specific gravity, water tolerance, and gel time increased while free formaldehyde content and viscosity were decreased. These results suggested that the amount of free formaldehyde strongly affected the reactivity of UF resin. Lowering F/U mole ratio of UF resin as a way of abating formaldehyde emission consequently requires improving its reactivity.

• The Korean Journal of Rheology
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• v.8 no.2
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• pp.119-128
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• 1996

폴리프로필렌(PP)/폴리카보네이트(PC) 블렌드의 유변학적 고찰을 통해 블렌드의 수 축현상과 분상상의 변형의 연관성을 연구했다. 블렌드의 수축현상은 압축과정에서 변형됐던 분산상이 고온에서 다시 원래의 무변형 상태로 복귀하면서 나타나는 탄성변형의 풀림으로 추정되고 압출팽윤의 데이터와도 부합된다. 압출온도를 최대한 낮게 해서(25$0^{\circ}C$) 제조한 블 렌드의 경우가 최대한 높게 한 경우 (29$0^{\circ}C$)보다 수축이더 큰 사실을 설명하기 위하여 순수 PC와 PP의 전단점도비와 신장점도비를 측정 비교한 결과 두 값이 공히 높은 온도의 경우 가 오히려 작게 되어 점성에 의한 분산상의 전단변형이나 신장변형이 수축의 원인이 아니라 는 것을 알아다. 한편 법선응력과 전단응력의 데이터로부터 얻은 물질풀림시간의 비는 낮은 온도의 경우가 작아서 수축현상이 분산상의 탄성에 의한 변형이라는 것을 확인했다.