• Journal of the Korean Chemical Society
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• v.8 no.1
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• pp.9-14
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• 1964

The viscosities of strong electrolytic solutions, such as KCl, KI and NaI have been measured over a fairy wide range of concentration variation (from 0.00002 to 3.7M). It was hoped that a study of the data in the light of modern theories on solution might reveal new relation between viscosity and surface tension of electrolytic solution. To secure more accurate measurements of viscosity and surface tension of the solutions, Ostwald viscometer was made with pyrex glass and modified the timing system for the transit of the meniscus with a new electronics system and with a pulse counter. As the experimental data obtained were in good agreement with the Jone's values, Jones-Dole equations for the electrolytic solutions were deduced, ${\eta}KCl\;=\;1\;+\;0.0052{\sqrt{c}}\;-\;0.01612c\;+\;0.00808c^2\;at\;30^{\circ}C$ ${\eta}KI\;=\;1\;+\;0.0220{\sqrt{c}}\;-\;0.01290c\;+\;0.02988c^2\;at\;25^{\circ}C$${\eta}Na\; =\;1\;+\;0.0240{\sqrt{c}}\;-\;0.0640c\;+\;0.03268c^2\;at\;25^{\circ}C$Gruneisen effect appeared in the dilute solution, whereas anti-Gruneisen effect was found for the extremely dilute solution. No satisfactory interpretation for the variation of the viscosity with concentration can be found at the present.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.70-79
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• 1998

The PEG and PCP have been used as a binder of high energy and minimum smoke propellant. In this study, PEG, PCP 0260, PCP 1270 and mixed PEG/PCP as a prepolymer were used, and also used BTTN/DEGDN and BTTN/TMETN as a plasticizer. Before being cured, the solution viscosity of prepolymer and plasticizer was measured with various contents of PCP in PEG and contents of plasticizer at $20^{\cire}C$~$60^{\cire}C$. The results were shown the increased concentration of PCP enhanced the viscosity of solution due to the hydrogen bond of PCP, and the increased contents of plasticizer undoubtedly decrease the viscosity of solution. The cured binders were tested for mechanical properties and measured for glass transition temperature with various concentration of PCP in PEG and contents of plasticizer. The increased concentration of PCP has shown better mechanical properties. This results were attributed to the H-bond. Also, the glass transition temperature was lowered with the higher contents of PCP Finally, with the higher content of PCP in PEG, the better mechanical properties and the lower glass transition temperature and the higher viscosity of solution were shown.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.1
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• pp.241-250
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• 1990

Characteristic relaxation time and characteristic diffusion time of viscoelastic fluids are determined experimentally by measuring the zero-shear-rate viscosity by falling ball viscometer and the infinite-shear-rate viscosity by capillary tube viscometer. Fluids used in experiments are aqueous solutions of polyacrylamide Separan AP-273 and the polymer concentrations range from 300 to 2000 wppm. A newly designed laser beam and timer system is employed to overcome the difficulty in measuring terminal velocities of the low concentration solutions. Ball removal device is prepared to remove the dropped ball from the bottom of cylinder without disturbing the testing fluid. In order to measure the zero-shear-rate viscosity, densities of hollow aluminium balls are adjusted very close to the densities of testing fluids. Characteristic diffusion time, which is ball viscometer. However, terminal velocity of a needle by falling ball viscometer is not affected by the time interval of dropping needles and characteristic diffusion time is not measured with a dropping needle. Powell-Eyring model predicts the highest values of the characteristic relaxation times among models used for heat transfer experimental works for a given polymer solution. As degradation of a polymer solution continues, the zero-shear-rate viscosity decreases more seriously than the infinite-shear-rate viscosity. Characteristic relaxation times of polymer solutions decreases as degradation continues.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.95-96
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• 2002

The operation of proceeding bearing in the conditions of misaligned axis of proceeding and bush leads to the load concentration on the bearing edges causing further mixed lubrication conditions, unstable operation and intensive wear of mating parts. For the design process of proceeding bearing the knowledge of static characteristics determined from the oil film pressure and temperature distribution is very important. For the 3-lobe proceeding bearing, the pressure, temperature and viscosity fields, load capacity, minimum oil film thickness, power loss, oil flow and maximum oil film temperature have been determined by iterative solution of the Reynolds', energy and viscosity equations. The paper introduces the results of theoretical investigations of static characteristics of 3-lobe proceeding bearing operating at misaligned axis of proceeding and bush. An effect of misalignment ratio, length to diameter ratio of the proceeding bearing, the lobe clearance ratio on the static characteristics was investigated. Laminar, adiabatic model of oil film for the solution of Reynolds, energy and viscosity equations was applied.

• Textile Coloration and Finishing
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• v.13 no.6
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• pp.435-440
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• 2001

This study investigates the rheological properties of in-situ polymerized solutions of polyacrylonitrile(PAN) and acrylonitrile(AN) -itaconic acid(IA) in dimethyl sulfoxide(DMSO) in terms of temperature, concentration, and time. The complex viscosity and storage modulus of the solutions were generally increased with elapsing time, which is ascribable to the three-dimensional pseudostructures formed by strong inter- or Intra-molecular attractions through Polar -CN and -COOH groups. The three-dimensional pseudonetworks would lead to relation of the acrylic solutions in long term. This was more noticeable at higher temperature within the temperature range examined. In the case of 20% solutions one can not observe lower Newtonian flow region in the viscosity curve. Disappearance of lower Newtonian flow region is indicative of heterogeneity of the solution system. Casson Plot of the viscosity data revealed that 20% solutions of PAN and AN-IA copolymer in DMSO clearly demonstrated positive yield stress, ascertaining formation of pseudostructures in the solution systems.

• Textile Coloration and Finishing
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• v.13 no.6
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• pp.77-77
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• 2001

This study investigates the rheological properties of in-situ polymerized solutions of polyacrylonitrile(PAN) and acrylonitrile(AN)-itaconic acid(IA) in dimethyl sulfoxide(DMSO) in terms of temperature, concentration, and time. The complex viscosity and storage modulus of the solutions were generally increased with elapsing time, which is ascribable to the three-dimensional pseudostructures formed by strong inter- or intra-molecular attractions through Polar -CN and -COOH groups. The three-dimensional pseudonetworks would lead to gelation of the acrylic solutions in long term. This was more noticeable at higher temperature within the temperature range examined. In the case of 20% solutions one can not observe lower Newtonian flow region in the viscosity curve. Disappearance of lower Newtonian flow region is indicative of heterogeneity of the solution system. Casson Plot of the viscosity data revealed that 20% solutions of PAN and AN-IA copolymer in DMSO clearly demonstrated positive yield stress, ascertaining formation of pseudostructures in the solution systems.

• 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.

• Bulletin of the Korean Chemical Society
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• v.15 no.5
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• pp.399-404
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• 1994

The non-Newtonian viscosities (the specific or intrinsic viscosities) of poly(L-proline) (PLP, $M_v$=19,000 and 32,000) in various mixed-solvent systems like water-propanol and acetic acid-propanol of varying compositions were measured during the reverse mutarotation (Form II ${\rightarrow}$Form I) by the application of external pressure (up to 4.5 psi). The non-Newtonian viscosity effect was found to be larger in acetic acid-propanol system than in water-propanol system and to somewhat decrease during the reverse mutarotation at a given solvent system. The non-Newtonian viscosity behavior of PLP in aqueous salt ($CaCl_2$) solution was also studied, from which it was found that the degree of the non-Newtonian effect decreased with increasing salt concentration, and increased with increasing PLP molecular weight. These findings could be explained in terms of conformational changes of PLP in solution (like the helix-helix or helix-coil transition) involved.

• Journal of the Korean Mathematical Society
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• v.48 no.4
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• pp.867-885
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• 2011

We study a class of quasilinear wave equations with strong and nonlinear viscosity. By using the perturbation method for semilinear parabolic equations, we have established the fundamental results on existence, uniqueness and continuous dependence on data of weak solutions.

• Journal of the Korean Mathematical Society
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• v.44 no.2
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• pp.443-453
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• 2007

We study the equation of a membrane with strong viscosity. Based on the variational formulation corresponding to the suitable function space setting, we have proved the fundamental results on existence, uniqueness and continuous dependence on data of weak solutions.