• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.539-542
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• 1999

In this study, acrylate salt material of new chemical composition for injection grouting was prepared in the state of aqueous solution, and the chemical and physical properties of the material were investigated. The gelation time of the material was freely controllable through the control of added catalysts amount. As the viscosity of the material was very low (2∼3cps), its injection efficiency was expected to be very excellent. The variation of its viscosity plotted with the process of gelation revealed that the efficiency of its penetration into the ground soil was very excellent. The LD$\sub$50/ test on white mouse verified the toxicity of the material was very slight and substantially negligible. The grouting effect using the material was examined through field case histories.

• Journal of Energy Engineering
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• v.7 no.2
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• pp.180-186
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• 1998

In this study, the effect of shear rate on the viscosity variation is examined to understand the flow characteristics of the mixture of bentonite and water. The variation of film thickness according to mixing ratio and viscosity is measured to characterize the film formation. And, the separation of dried film is studied according to film thickness. Specific surface area affecting on adsorption capability is measured using BET method. The viscosity decreases and the film thickness increases as the mixing ratio increases. The separation characteristic of dried film is suitable within a range of 40 to 150 ${\mu}{\textrm}{m}$ in film thickness and 5 to 10% in mixing ratio.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.382-386
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• 2011

In this study, a CFD code is developed to perform simulation of the surface and internal flow of a three-dimensional rectangular cavity driven by an external gas flow. Investigated in this study are surface characteristic such as surface tension, surface dilational viscosity(or surface elasticity), and surface viscosity. Visualization of the surface of water is performed to compare with the numerical results obtained with the developed in-house code. We have found that the surface flow is very sensitive to the surface tension and other configurations. The surface flow velocity obtained from the numerical solution is lower than the experimental result.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.546-551
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• 2005

In this paper we report fluid flow characteristics of $AL_2O_3$ nanoparicles suspended in water. Especially, the effects of volume fraction with the range of 0.01% to 0.3% and inner diameter of tubes on the pressure drop and the effective viscosity of $AL_2O_3$ nanoparicles suspended in water are experimentally investigated. Experimental results are compared with analytic solution which can be derived with Einstein model. We confirm whether Einstein model which have been used to determine the effective viscosity of nanofluids is valid or not.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.2
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• pp.49-57
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• 2001

This thesis attempts to study ink transition for on the polycarbonate multicalculator plate for automobile. For this study, the change of weight by screen printed ink transition on polycarbonate material by ink viscosity(be diluted ; 0%, 5%, 10%, 20%) was observed. The weight by screen printed ink is depended on amount of added solvent. We have studied change of the weight by the transition of the ink that was screen-printed on polycarbonate which is to be printed according to the viscosity of the ink (diluent: undiluted solution 5%, 10%, 15%, 20%). This shows that ink transition become activated since the amount of ink(or/and the viscosity of ink) is increased.

• Journal of the Ergonomics Society of Korea
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• v.9 no.1
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• pp.29-33
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• 1990

The need for the protection of workers in many industrial workstations has long been recognized, and many type of protective equipment have been devised. In many protective equipment designs, this study set limits to the safety helmet. The direct closed head impact problem was idealized as a linear-damped spring model. This study concerns what properties of helment should afford optimal protection in a direct closed head impact problem. The solution to the problem was achieved through analytic method and numerical computation. The answer was found in terms of 4 parameters : 1) rigidity of shell, 2) viscosity of shell, 3)rigidity of harness, 4) viscosity of harness. The choices are as follows 1) to reduce the rigidity value of harness as small as possible 2) to increase the viscosity value of harness as large as possible. 3) to select the rigidity value of shell sufficient for preventing a breakage.

• Bulletin of the Korean Chemical Society
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• v.4 no.2
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• pp.68-72
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• 1983

The $pK_{a}$ of $-NH_{3}^{+}$ group of chitosan in water was 6.2, while that of D-glucosamine-HCl, monomer of chitosan, was found to be 7.8. The difference of $pK_{a}$ values between chitosan and D-glucosamine was attributed to the strong electrostatic interaction between $-NH_{3}^{+}$ groups in chitosan. The apparent binding constant of $Cu^{2+}$ to D-glucosamine was estimated to be $1{\times}10^{4}$. For chitosan, no significant binding of $Cu^{2+}$ to the polymer was observed when pH < 5, but strong cooperative binding was observed near pH 5.1. The mechanism of such cooperativity was proposcd. Chitosan in solution exhibited typical polyelectrolytic behaviors: viscosity increases with increased amount of charged group, and decreases with addition of salt. The concentration dependence of viscosity was measured, and the Huggins parameters and intrinsic viscosity were calculated at various ionic strength. The results were interpreted in terms of molecular properties of the chitosan molecule.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.99-100
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• 2002

Radial, tilting-pad proceeding bearings are applied in high speed rotating machines operating at stable small and mean loads and the peripheral speeds of proceeding reaching 150 m/s. The operation of bearing can be determined by static characteristics including the oil film pressure, temperature and viscosity distributions, minimum oil film thickness, load capacity, power loss, oil flow. The operation of 5-lobe tilted-pad proceeding bearing has been introduced at the assumption of adiabatic oil film. The oil film pressure, temperature and viscosity distributions habe received by iterative solution of the Reynolds', energy and viscosity equations. The resulting oil film force, minimum oil film thickness, power loss. oil flow, maximum oil film pressure, maximum temperature were computed for different sets of bearing geometric parameters as: bearing length to diameter ratio, pad angular length and width as well as pad relative clearance.

• Geomechanics and Engineering
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• v.36 no.1
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• pp.19-26
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• 2024

Erigen's nonlocal thermoelasticity model is used to study the effect of viscosity on a micropolar thermoelastic solid in the context of the multi-phase-lag model. The harmonic wave analysis technique is employed to convert partial differential equations to ordinary differential equations to get the solution to the problem. The physical fields have been presented graphically for the nonlocal micropolar thermoelastic solid. Comparisons are made with the results of three theories different in the presence and absence of viscosity as well as the gravity field. Comparisons are made with the results of three theories different for different values of the nonlocal parameter. Numerical computations are carried out with the help of Matlab software.

• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.497-502
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• 1997

For the purpose of enzymatic production of galactooligosaccharides from soybean arabinogalactan (SAG) hydrolysis, the $\beta$-1, 4-D-arabinogalactanase($\beta$-1, 4-galactanase) from Bacillus sp. HJ-12 was used. The soybean galactooligosaccharides(SOS) were optimally produced in SAG 1%(w/v), pH 8.0, 5$0^{\circ}C$, $\beta$-1, 4-galactanase 20unit/g SAG and 24-40 hour reaction conditions. The produced galactooligosaccharides had visocity of 11,000 cp at 75%(w/v), $25^{\circ}C$. The viscosity of galactooligosaccharides was 80 fold increasing value than that of sucrose solution. Temperature dependence of viscosity of SOS was 4.6 fold higher value than surose solution below than 5$0^{\circ}C$. Less than 50 Brix, the viscosity of SOS was similar with sucrose solution(20-40 cp), but increasing of concentration, the difference of viscosity between SOS and sucrose solution was increased. And, SOS was very stable at pH and temperature.