• Korea-Australia Rheology Journal
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• v.12 no.1
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• pp.77-81
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• 2000

Rheological behavior of thermoset/thermoplastic blends of epoxy/polyethersulphone (PES) was monitored during curing of the epoxy resin. During the isothermal curing of the mixture, a fluctuation in viscosity just before the abrupt viscosity increase was observed. This fluctuation is found to be due to the phase separation of PES from the matrix epoxy resin during the curing. The experimentally observed viscosity fluctuation is simulated with a simple two phase suspension model in terms of the increase in domain size. The viscosity profiles obtained experimentally at different isothermal curing temperatures are in good agreement with the predictions from the simple model taking into account the viscosity change due to the growth of PES domain and the network formation of the epoxy matrix.

• The Korean Journal of Food And Nutrition
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• v.7 no.4
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• pp.353-360
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• 1994

Effect of pH, calcium, sucrose, heating and mixing ratio of soy and cow milk was studied on the viscosity and the sensory characteristics of cow-soy milk. The viscosity of soymilk was significantly affected by pH with showing maximum at 6.0 and the pH effect was decreased as the ratio of cow talk increased. A addition of sucrose or calcium affected little on the viscosity and a negative linear relationship was found be tween viscosity and an increase in cow milk ratio. Sensory characteristics of grassy and beany odor and taste of soymilk were rapidly decreased and nutty flavor and total acceptability were increased during initial 30 min of boiling. A further increase in boiling affected little on tastes and odors of soymilk. The beany odor and taste linearly decreased and milk flavor Increased as the ratio of cow milk increased. The total acceptability of 50 : 50 was found to be maximum for cow and soy mixed milks.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.78-84
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• 2014

Viscosity agents were added to water to improve extinguishing performance of low pressure water mist suppression system on wood cribs fire, and a small scale wood cribs fire experiment was conducted to measure the extinguishing performance. CMC and agar were used for viscosity agent and as the amount of viscosity agent enlarges, it showed the increase of the viscosity of aqueous solution and the decrease of the fluidity. On wood cribs fire experiment, the extinguishing efficiency was improved with supplemental viscosity agent as it enhanced the adhesive time of aqueous solution on the wood, and therefore expanded the contact time of fire surface. The surface tension of aqueous solution was decreased with the addition of agar which to be assumed as an increase factor of extinguishing efficiency. By the extinguishing experimental result, the most effective extinguishing agent was CMC 0.6 wt.%, with the flame suppression time and the extinguishing time were reduced by 70s and 93s respectively at this concentration.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.615-621
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• 1996

Experiments were carried out in humans to assess the relationship between viscosity and post-prandial glucose response of soluble fibers. Eight(3 male and 5 female) healthy individuals were tested for their glucose response after taking control meals or 3 test fiber meals of different viscosities. Meal viscosity of the test food was adjusted to be between 200 and 70, 000 cps. There was a significant increase in post-prandial glucose response(p=0.01) in control meals by solely increasing the volume of water. Fiber with the highest viscosity konjac mannan demonstrated the lowest relative glucose response(70.1$\pm$6.6), followed by medium viscosity xanthan (79.3$\pm$8.7)and low viscosity psyllium (86.3$\pm$10.5). The difference is significant at the level of p<0.05. However, no significant difference in relative glucose response of the same fiber was found when the 4 levels of water were added to make different meal viscosity of each fiber (p=0.476). This result suggested that hypoglycemic action of soluble dietary fibers is related to fiber viscosity rather than meal viscosity.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.17-26
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• 1988

The polysaccharide produced by pseudomonas elodea, Gellan gum, was rheologically characterized, compared with agar. Rheological properties were determined from the change in the value of intrinsic viscosity with the pH and salt concentration. At the range of pH 2∼ll and salt 0∼0.16M KC1, the intrinsic viscosity of Gellan gum ranged from 8.8 to 21.2dl/g and agar ranged from 1.97 to 11.46d1/g. In the absence of salt, the intrinsic viscosity of Gellan gum increased as the pH of solution increased up to neutral pH then decreased slightly at alkaline pH, whearas the intrinsic viscosity of agar increased as the pH of solution increased up to pH 9 then decreased slightly. Intrinsic viscosity of Gellan gum and agar decreased with an increase in salt concentration. The chain stiffness parameter for the Gellan gum was 0.033. The overlap parameter of Gellan gum and agar were 0.047g/dl and 0.087g/dl, respectively. Gellan gum and agar were shear rate dependent or pseudoplastic. The yield stress and proportionality constant of Gellan gum increased slightly as the concentration increase, on the other hand, the shear index of Gellan gum showed a maximum at 0.75g/dl and gradually decreased as the concentration increase. The apparent viscosity of Gellan gum and agar decreased as the temperature increase. A lower concentration of the divalent cations calcium and magnesium is required to obtain maximum gel strength than for the monovalent cations sodium and potassium.

• Preventive Nutrition and Food Science
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• v.13 no.1
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• pp.40-44
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• 2008

Response surface methodology (RSM) was used for analyzing the manufacturing process of Prunus mume extract-added vinegared red pepper paste (maesil chokochujang) with respect to sensory quality properties. Experiments were carried out according to a central composite design, selecting the amount of kochujang, amount of maesil extract, and type of sugar in the mixture as independent variables; sensory attributes such as flavor, taste, color, and mouthfeel viscosity as response variables. The polynomial models developed by RSM for sensory color and mouthfeel viscosity were highly effective to describe the relationships between the factors studied and the responses. The estimated response surfaces confirmed that the amount of kochujang had a positive effect on color (p<0.001) whereas the amount of maesil extract had a positive effect on mouthfeel viscosity (p<0.001). Increase in the amount of kochujang led to a sharp increase of the sensory score on color at all the maesil extract and sugar type levels. On the other hand, increase in the amount of maesil extract caused a sharp increase in the mouthfeel viscosity value regardless of kochujang concentration and type of sugar. The differences among samples made with different types of sugar were not significant (p>0.05).

• Journal of Pharmaceutical Investigation
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• v.26 no.4
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• pp.263-271
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• 1996

Sulconazole nitrate(SCN), an imidazole derivative which has been effective in the treatment of dermatophytosis, tinea versicolor and candidiasis, was formulated as a gel containing drug, poloxamer 407, ethanol and propylene glycol. The resulting SCN gels were evaluated with respect to their viscosity, drug release rate, skin permeation rate. The apparent viscosity of SCN gel increased in proportion to poloxamer 407, drug and propylene glycol concentration. In case ethanol was added, the apparent viscosity decreased. The drug release rate of SCN gel increased in proportion to temperature and ethanol concentration. But the drug release rate decreased as the concentration of poloxamer 407 increased. The increase of drug concentration induced nonlinear increase of drug release rate. When propylene glycol was added at the level of 10%, the drug release rate increased but from 15% it decreased. The skin permeation rate decreased in high concentration of poloxamer 407. The skin permeation rate of SCN gel containing 15% ethanol increased about twice than that of gel without ethanol. The increase of drug concentration induced nonlinear increase of skin permeation rate. When propylene glycol was added at the level of 10%, the skin permeation rate increased but from 15% it decreased.

• Food Science of Animal Resources
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• v.18 no.3
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• pp.209-215
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• 1998

Effects of protein concentration, ionic strength, pH, and temperature range on the heat-induced denaturation of salt soluble protein extracted from spent layer meat were investigated. Viscosity of salt soluble protein heated at 65$^{\circ}C$ for 30 min began to increase sharply above 7 mg/ml of breast protein concentration, and above 21 mg/ml of leg protein concentration, respectively. Both turbidity and viscosity showed the highest value in cooked protein solution with pH 6.0 and 1% NaCl. The turbidity of salt soluble protein started to increase continuously from 40$^{\circ}C$ to 80$^{\circ}C$. The viscosity increased rapidly from 45$^{\circ}C$ to 60$^{\circ}C$ in breast protein, and increased from 50$^{\circ}C$ to 55$^{\circ}C$ in leg protein, respectively, and then kept relatively constant. Breast protein had higher viscosity than leg protein during heat-induced gelation. Therefore, salt soluble protein from spent layer meat was associated with denatured protein (turbidity change) prior to gelation (viscosity change) during heating. Breast protein showed lower thermal transition temperature, and better gel formation than leg protein during heating.

• Polymer(Korea)
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• v.35 no.1
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• pp.23-29
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• 2011

We measured shear viscosity of polymeric particles, prepared by suspension polymerization with hydrophobic silica as a stabilizer at $75^{\circ}C$, by a capillary rheometer. Shear viscosity displayed a non-Newtonian behavior with an increase in weight average molecular weight. Measurement of shear viscosity at 170 and $190^{\circ}C$ with copoly(styrene/butyl methacrylate) (co-PSB) particles by varying the ratio between styrene (St) and butyl methacrylate (BMA) showed that shear viscosity was a function of molecular weight, temperature and compositional ratio. When the ratio was 7/3, 5/5 and 3/7, shear viscosity slightly reduced with an increase in BMA concentration despite similar weight average molecular weights. We found that shear viscosity of copolymers with BMA concentrations exceeding 70% displayed a sharp reduction at high shear rates. It is speculated that increased PBMA chain length contributes to enhanced flowability of copolymers. When carbon black was incorporated into co-PSB, shear viscosity progressively increased with increasing carbon black concentration. The increase in shear viscosity, however, was less pronounced compared to the cases of molecular weight increase.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.881-889
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• 1998

For the application of the commercially modified starch in frozen and retort foods, apparent viscosity and water loss were measured at each stages of heating, sterilization and freezing-thawing stages. Apparent viscosity showed the exponential increase with concentration and the slopes of apparent viscosity against concentration in the Firm-Tex(hydroxypropyl distarch phosphate), Hi-Flo(acetylated distarch adipate) and Colflo 67(acetylated distarch adipate) from waxy maize starch were higher than those of Amyloacetate M20(starch acetate) and X-amylo 250(distarch phosphare) from potato starch. In the presence of 1 or 2% NaCl, X-amylo 250 among modified starches showed the increase in water loss and the decrease in apparent viscosity, whereas Colflo 67, Hi-Flo and Firm-Tex were little affected by NaCl. In the presence of 1 or 2% sucrose, water loss and apparent viscosity of the modified starches were not affected. In the range of pH 4~8, water loss and apparent viscosity of the modified starches had no change but the differences were detected to some extent between each of heating, sterilization and freezing-thawing stages. In the apparent viscosity and water loss of the modified starches after 3 week storage from heating and sterilization, Hi-Flo, Amyloacetate M20 and X-amylo 250 were not changed at the storage period, and the overall acceptability of retort food containing the modified starches such as Firm-Tex and Amyloacetate M20 were favored more than others. In the apparent viscosity and water loss of the modified starches which have been frozen and thawed three times repeatedly, Colflo 67, Hi-Flo and Firm-Tex were not changed in freezingthawing, and the overall acceptability of frozen food containing Firm-Tex was most favored.