• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.17-25
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• 1997

Natural water-soluble polymers such as starch, casein and carboxy methyl cellulose(CMC) have been limited in their uses. However, the proper water retention of coating colors can not be obtained without addition of these polymers. Furthermore, the coating runnability and the physical properties of coated paper were not also satisfied. Therefore, the objective of this study was to synthesize the water retention and flow modifiers which can improve the water retention and flow properties of coating colors. We have measured physical properties of flow modifiers and coating colors which included flow modifiers. The viscosity of flow modifiers was very low at acid pH, and rapidly increased at about pH 7, and gradually reached to equilibrium at alkali pH. Such an increase comes from the molecular weight of flow modifiers and the amount of acrylic and methacrylic acids. The viscosity of coating color containing the flow modifiers was lower than that containing CMC. However, both of them had little difference in water retention. The water-phase viscosity of synthetic modifier containing coating color was either higher or similar compared to that of CMC containing coating color. The high shear viscosity of coating colors was low. Therefore, it can be concluded that the synthetic flow modifiers are very useful for improvement of flow properties and water retentions.

• Restorative Dentistry and Endodontics
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• v.28 no.3
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• pp.209-221
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• 2003

The objectiveness of this study was to evaluate whether low-viscosity composite can bond effectively to dentin surface without bonding resin. The low-viscosity composites being 50wt% filler content were made by the inclusion of bonding resin of two self-etching systems(Cleafil SE Bond, Unifil Bond) varied with contents as 0, 10, 20, 30, 40, 50wt%. Exposed dentin surfaces of extracted 3rd molars are used. Dentin bond strengths were measured. The tests were carried out with a micro-shear device placed testing machine at a CHS of 1mm/min after a low-viscosity composite was filled into an iris cut from micro tygon tubing with internal diameter approximately 0.8mm and height of 1.0mm. 1 Flexural strength and modulus was increased with the addition of bonding resin. 2. Micro-shear bond strength to dentin was improved according to content of bonding resin irrespective of applying or not bonding resin in bonding procedure, and that of Clearfil SE Bond groups was higher than Unifil Bond. 3. There were no significant difference whether use of each bonding resin in bonding procedure for S-40, S-50, U-50(p＞0.05). 4. In SEM examination, resin was well infiltrated into dentin after primed with self-etching primer only for S-50 and U-50 in spite of the formation of thinner hybrid layer. Low viscosity composite including some functional monomer may be used as dentin bonding resin without an intermediary bonding agent. It makes a simplified bonding procedure and foresees the possibility of self-adhesive restorative material.

• Geomechanics and Engineering
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• v.18 no.3
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• pp.259-266
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• 2019

This paper presents a comparison between experimental measurements and numerical estimations of penetration length of a cement grout injected in discrete joints. In the experiment, a joint was generated by planar acryl plates with a certain separation distance (; aperture) and was designed in such a way to vary the separation distances. Since a cement grout was used, the grout viscosity can be varied by controlling water-cement (W/C) ratios. Throughout these experiments, the influence of joint aperture, cement grout viscosity, and injection rate on a penetration length in a discrete joint was investigated. During the experiments, we also measured the time-dependent variation of grout viscosity due to a hardening process. The time-dependent viscosity was included in our numerical simulations as a function of elapsed time to demonstrate its impact on the estimation of penetration length. In the numerical simulations, Bingham fluid model that has been known to be applicable to a viscous cement material, was employed. We showed that the estimations by the current numerical approach were well comparable to the experimental measurements only in limited conditions of lower injection rates and smaller joint apertures. The difference between two approaches resulted from the facts that material separation (; bleeding) of cement grout, which was noticeable in higher injection rate and there could be a significant surface friction between the grout and joint planes, which are not included in the numerical simulations. Our numerical simulation, meanwhile, could well demonstrate that penetration length can be significantly over-estimated without considering a time-dependency of viscosity in a cement grout.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.329-329
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• 2017

The study was conducted to investigate the effects of different harvesting time on pasting properties of starch in three colored rices. Seven major parameters of starch pasting properties, peak viscosity (PKV), hot pasting viscosity (HPV), cool pasting viscosity (CPV), setback (CPV minus PKV), breakdown (PKV minus HPV), peak time, and pasting time were determined by Rapid Visco Analyzer. The peak viscosity, hot viscosity, cool viscosity and peak time were influenced by different harvesting times. Pasting time was delayed slightly with prolonged harvesting time in all rice cultivars. Pasting temperature in each rice cultivar differed from each harvesting time, and pasting temperature of the two rice cultivars, Hongjinju and Joseongheugchal, showed the highest at the 40 days after heading and then it decreased at the final harvesting time. With the delay of the harvesting time, peak viscosity, hot viscosity, cool viscosity, setback value and pasting temperature did not exhibit a regular trend depending on their genetic characteristics. Branch chain length distribution of amylopectin was demonstrated a distinct difference among these colored rices. In changes of amylopectin branch chain-length distribution, the amylopectin structure of Hongjinju rice cultivar as affected by different harvesting time, the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant increase in A chains with $DP{\geq}12$ and remarked decrease in long chains $37{\leq}DP$ compared to that of 30, 40, and 50 days after heading. In particular, when harvesting time is delayed the distribution percentage of short chain (A chains with $DP{\geq}12$) was increased except for the rice which harvested 20 days after heading. The similar results were also observed in Sintoheugmi rice cultivar like that of Hongjinju rice cultivar. Otherwise, distribution percentage of the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant decrease in A chains with $DP{\geq}12$ and remarked increase in B chains $13{\leq}DP{\geq}24$ compared to that of 30, 40, and 50 days after heading.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.107-114
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• 1999

To find the best combustion conditions in the heavy oil burner kinetic viscosity of heavy oil A, B and C at different temperature range, from 40 to 140$^{\circ}C$, and the droplet sizes of the heavy oils at different temperature and pump pressure were measured. And, combustion characteristics were investigated under the different conditions : two different heavy oil and three different oil temperature. At temperature of 70, 100, 130$^{\circ}C$ the kinetic viscosity of heavy oil A and B are 7.9, 5.7, 4.3 and 30.4, 13.7, 7.9cSt, respectively. The greatest and smallest viscosity were 7,455 cSt at C oil on 27$^{\circ}C$ and 4.26cSt at A oil on 140$^{\circ}C$. The magnitude of viscosity difference between at 100$^{\circ}C$ and 140$^{\circ}C$ under 6 cSt in cases of A and B oil, but more than 30cST on C oil. Of the droplet sizes, the biggest and smallest droplet size in A oil were 98$\mu\textrm{m}$ at oil temperature of 130$^{\circ}C$(4.3cSt), pump pressure of 1.57MPa and 72$\mu\textrm{m}$ at 70$^{\circ}C$(7.9cSt), 2.35MPa, respectively. It appeared that as spraying pressure increased the droplet size decreased, however, no distinct differences were found in the effects of kinetic viscosity on the droplet sizes of the test range. The best combustion performance was observed when droplet size, spraying pressure and oil temperature were 73$\mu\textrm{m}$, 2.35MPa and 70$^{\circ}C$ producing CO2 of 13.1%, CO of 13ppm and flue gas temperature of 250$^{\circ}C$ in A oil combustion For B oil, it was100$^{\circ}C$, 2.35MPa, 52$\mu\textrm{m}$, producing CO2 of 10ppm and flue gas temperature of 260$^{\circ}C$. In general, it appeared that better combustion results were observed in the smaller droplets produced burner condition.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.200-206
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• 1998

The effect of surface tension and viscosity of polymer solution on the thickness of water casting membranes was studied. Spreading of polymer solutions on water surface was governed by the surface tension and viscosity of the polymer solution. The thickness of water casting membrane was affected by these two factors. The properties, mentioned above, were proportional to the polymer concentration. The order of magnitude in surface tension was PVC>PS>CA and that of viscosity was CA>PS>PVC. The difference of surface tension between water and polymer solution acts as driving force for spreading of polymer solution, but the viscosity as resistance. The thickness of polymeric membrane prepared by water casting was PS>CA>PVC. The order of membrane thickness was not as same as that of surface tension. This phenomena were due to the viscosity which acts as more effective spreading resistance than the surface tension.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1175-1179
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• 1999

The rheological properties of highly filled epoxy molding compound(EMC) for semi-conductor encapsulants are greatly affected by the content of filler loaded. In this study, the change of viscosity of EMC for semi-conductor encapsulants with the filler content was investigated. Also, both of Cox-Merz and modified Cox-Merz equations were applied to convert the viscosity change as a function of frequency to that of shear rate. It was ovserved that shear thinning and yield stress occured at high filler contents and that the Cox-Merz equation could not be applied at high filler contents because of the difference of viscosity according to the various strains. When the modified Cox-Merz equation was applied, the all the curves having different strain tend to be represented by one master curve, even though some deviation was obseved at high filler content and strain.

• Culinary science and hospitality research
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• v.16 no.3
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• pp.286-297
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• 2010

This study examines physiochemical characteristics of functional bread with black garlic flour added such as its content, texture, sensory test and quality properties. The loaf volume and weight of black garlic flour-added pan bread showed that for the control, the loaf volume was the greatest, and the more the black garlic flour content increased, the smaller the loaf volume became. The change of crust chromaticity showed that the L value decreased significantly, and crust chromaticity thickened, and as the black garlic flour content increased, a value and b value decreased. The characteristics of texture showed that the hardness and chewiness decreased as the black garlic flour content increased, and gumminess increased significantly while there was no significant difference in cohesiveness. The flavor, taste and texture of pan bread with black garlic flour content didn't showed a significant difference with the control. Consequently, the black garlic flour-added wheat flour was no significant difference with the control up to 3% black garlic flour-added wheat flour, which can be used as a product.

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.271-273
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• 2001

We present a 4-parameter implicit Lagrangean code which satisfies conservation of mass, linear and angular momenta, energy and entropy simultaneously. The primary advantage of this scheme is possibility to control dissipative properties of the scheme avoiding the effects of numerical viscosity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.877-887
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• 2015

We have proposed a new method for estimating the viscosity of the composite. In this paper, we have developed a device for measuring the injection mold cavity pressure. This makes it possible to verify the accuracy of the viscosity in CAE D/B in real time by measuring the melt pressure in the mold, and comparing this with the simulated pressure from the CAE analysis. Materials used in this study is a PP(Polypropylene), PP/LGF30%(Polypropylene/long glass fiber 50% composite) and PA66/LGF50%(Polyamide 6,6/long glass fiber 50% composite). The viscosity data for PP and PP long fiber composite have already been built, but the one for PA66 long-fiber composite does not exist because it is a newly developed material. Thus we obtained the viscosity curve of PA66/LGF50% by this system. Then, the viscosity curves from conventional viscometer were also compared with the viscosity obtained by the our method. And, we proved the accuracy of the CAE data of PP. In case of PP/LGF50% which is highly viscous and complex material, we improved the existing CAE data.because there was a difference between the measuring data and the CAE data.