• Geomechanics and Engineering
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• 제33권2호
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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.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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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

• 콘크리트학회논문집
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• 제16권2호
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• pp.147-154
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• 2004

국내의 경우 건설생산현장에서 고유동콘크리트의 제조시 주로 나프탈렌계 및 멜라민계가 적용되고 있으며, 또한 최근에는 콘크리트의 요구성능을 확보하기 위하여 이러한 두 성분을 혼합하여 적용하는 사례도 나타나고 있다. 따라서 본 연구에서는 고유동콘크리트의 유동특성에 영향을 미치는 고성능감수제의 구성비율을 비교$\cdot$분석함으로서 혼합형 고성능감수제의 현장적용시 적용방법 및 품질기준 확립을 위한 기초적인 자료를 제시하기 위하여 고성능감수제를 분산제의 구성비율에 따라 N, NM, MN, M의 4수준으로 설정하였다. 그 결과 고성능감수제 구성비율에 따른 페이스트의 유동특성은 나프탈렌의 구성비율이 증가할수록 상대플로우면적비 및 흡착률이 증가하고 있어 유동성이 우수하게 나타났으며 멜라민 구성비율이 증가할수록 점성이 높아지는 것으로 나타났다. 나프탈렌-멜라민 혼합형 고성능감수제의 경우 유동성 및 간극통과성을 포함한 고유동 특성과 응결시간에 있어서 상대적으로 양호한 성능을 나타내고 있어 고유동콘크리트 제조시 고성능감수제를 구성하는 주요성분을 적절하게 혼합하여 사용함으로서 고성능감수제의 효율적인 성능향상이 가능할 것으로 사료된다.

• Tribology and Lubricants
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• 제14권1호
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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.

• 한국분무공학회지
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• 제14권3호
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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.

• 동아시아식생활학회지
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• 제15권5
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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.

• 에너지공학
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• 제8권2호
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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.

• 동아시아식생활학회지
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• 제11권4호
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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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• 제35권5호
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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.

• 한국식생활문화학회지
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• 제20권3호
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• pp.299-304
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• 2005

This study investigated the feasibility of the bread making process with the mixture of the functional rice flour. The bread was manufactured with 20, 30 or 40% functional rice flour with increasing and wheat flour. Gelatinization characteristics of the rice starch was examined by differential scanning calorimetry(DSC). Coated with soluble dietary fiber rice showed the highest gelatinization enthalphy among functional rices and other functional rices were similar to normal rice. in the viscosity point of view. generally the viscosity related to the addition ratio. The most viscose case was 30% Sangwhang rice but in fermented with monascus ruber rice case, viscosity was low even with 40% case because of the transformation of the starch granules. In sensory evaluation, the highest sensory scores for the uniformity of pore size and flavor were obtained when sangwhang rice flour content was 20%. The textual study was mainly focused on the hardness, cohesiveness, adhesiveness, springiness, chewiness. Textural characteristics of functional rice bread crumb bakedwith 20% coated with soluble dietary fiber rice, 20% sangwhang was low in hardness, chewiness and gumminess. Therefore, Sangwhang rice flour 20%, Monascous ruber 20% and Coated soluble dietary fiber rice 20% were considered to be the most suitable addition ratio for the rice breads.