• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.104-109
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• 2009

In this paper, polymer nanocomposites were fabricated by mixing fire-resistant and high pseudoplastic Nylon 6,6 with MWNT(Multiwalled Nanotube), which has mechanical, electrical, and heat stable properties. The experiments were performed in order to investigate their mechanical and electrical properties depending on the level of MWNT and the presence of acid treatment on Nylon 6.6. Morphology of polymer nanocomposites was observed using Scanning Electron Microscopy technique. The results indicate that the polymer nanocomposites have the best mechanical and electrical properties in the optimal conditions of Nylon 6.6 and MWNT(10wt%).

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.224-230
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• 2005

The effects of low viscosity chitosan on the rheological properties of soymilk using a model system and on tofu qualities were examined. The flow behavior of soy milk with chitosan closed the Newtonian flow and stabilized according to increasing chitosan concentration. The soymilk containing $glucono-\delta-lactone$ exhibited a more pseudoplastic flow behavior compared with that of the control soymilk. The addition of low viscosity chitosan to the tofu preparation did not significantly affect its physicochemical properties. However, the results of the TEM image and instrumental textural properties showed that low viscosity chitosan affected the construction of the tofu structure. Chitosan tofu had low scores across the whole field of appearance in the sensory evaluation, and its overall eating quality was scored significantly lower. These results suggest that the addition of low viscosity chit os an affects the quality of tofu, which changes according to the degree of polymerization and concentration of chitosan.

• Journal of the Korean Home Economics Association
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• v.26 no.3
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• pp.93-102
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• 1988

Rheological properties of cowpea and mung bean starch gels and pastes were investigated and compared with Instron Universal Testing machine and Brabender Viscometer. As the result of puncture test of gels, yield point force of mung bean starch gel was higher than that of cowpea starch gel. Compression coefficient of cowpea starch gel calculated by Bourne's equation was lower than that of mung bean starch gel. the stress relaxation test showed that viscoelastic properties of cowpea and mung bean starch gels may be represented by six element Maxwell model consisting of three Maxwell element in parallel. Cowpea and mung bean starch pastes showed bingham pseudoplastic behavior in 3, 5, 6, 7 and 8%. The consistency index in 7∼8% of cowpea starch paste were lower than those of mung bean starch paste. concentration dependence on consistency index and yield stress in mung bean starch were higher than those of cowpea starch. The yield stress of starch pastes was significantly correlated with yield point force by puncture test (r=0.996).

• KSBB Journal
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• v.10 no.5
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• pp.547-552
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• 1995

Some functional and rheological properties of the ${\gamma}$-polyglutamic acid(${\gamma}$-PGA) produced from alkalophilic Alcaligenes sp. were investigated. Viscosity synergism with thickening agents, capacities for gelling, entrapig of heavy metals, and flocculability of ${\gamma}$-PGA were not observed, but the relatively good compatability with various polyvalent metallic ins, excellent absorption ability and spinability were observed. The ${\gamma}$-PGA solution showed non-Newtonian flow behavior and exhibited pseudoplastic property with a yield stress at above 1% concentration. The values of flow index for 1% solution were in the range of 0.41∼0.75 showing shear rate dependency and the value of yield stress was 2.28 Pa. The value of consistency index was 0.868 Pa$.$Sn and was exponentially dependent on concentration.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.223-224
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• 2006

In this paper, rheological characteristics of Metal Injection Moulding (MIM) feedstock using locally binder of palm stearin are presented. The feedstock consisted of 316L-grade stainless steel powder with three different particle sizes and the binders comprise palm stearin and polyethylene. The viscosity of MIM feedstock at different temperatures and shear rates was measured and evaluated. Results showed that, the feedstock containing palm stearin exhibited suitable rheological properties and suitable to produce a homogeneous feedstock that is favorable for injection molding process.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.138-144
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• 1997

A new biopolymer YU-122 from Metarrhizium anisopliae (Metschn.) Sorok consisting of glucose and galactose was tested for its physical properties and flow behavior characteristics. Xanthan gum showed slightly higher viscosity than biopolymer YU-122. Viscosity of biopolymer YU-122 at various pHs and temperatures was also tested. The viscosity of biopolymer YU-122 was very stable up to pH 11 and $60^{\circ}C$, indicating that it has a great possibility for the application such as food additives, emulsifier, and drug release agents. Flow behavior index (n) from Power Law equation is 0.173. Biopolymer YU-122 solution was a pseudoplastic non-Newtonian fluid, which indicated that it had one or more side chains. When biopolymer YU-122 was used as a emulsifier, it stabilized the emulsion up to 120 hours, which was much better than xanthan gum. The biopolymer YU-122 could form an excellent but less clear film compared with xanthan and pullulan.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.442-448
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• 2015

The aim of this study was to investigate the effects of guar gum on the rheological behaviors, sensory attributes, and consumer acceptability of soft tofu stew sauce. Five different soft tofu stew sauces were commercially manufactured with various levels of guar gum (0.0, 0.1, 0.2, 0.4, and 0.5%). Twelve sensory attributes of the stew sauces were identified by nine trained descriptive panelists, whereas hedonic levels of the stew sauces were assessed by a group of 51 consumers. Steady flow of the stew sauces were measured by a rheometer. Significant differences were observed in terms of sensory saltiness and viscosity among the products. For the consumer test, 0.1% guar gum-added product was most liked by consumers. Partial least square regression showed sensory shellfish, green onion, and shrimp flavors to be key factors affecting overall acceptability for the stew sauces. For rheological behaviors, 0.0, 0.1, and 0.2% guar gum-added products showed newtonian behaviors ($R^2$=0.99 by power law model), whereas 0.4 and 0.5% products followed pseudoplastic behaviors ($R^2$=0.99 by power law model). Based on the established equivalence table using rheological and consumer data, smaller than 0.0114 ($Pa{\cdot}s$) of the apparent viscosity should be necessary to guarantee 'slightly like' category in a consumer hedonic test. It seems that addition of guar gum not only influenced rheological properties but overall acceptability for the stew sauces.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.716-721
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• 1996

To bring out the functional properties of Agar-agar extracted with 0.01N $H_2SO_4$ from Gellidium amansii produced in Che-ju Udo and its fluid properties were investigated. The yield of agar from Gellidium amansii produced was $32.7\%$, the content ratio of agarose and agaropectin was 79 to 21, gelation ability was $0.19\%$ and jelly strength was $413.8\;dyne/cm^2$. Agar-agar solution showed the movement of non-Newtonian fluid and pseudoplastic property was emerged as its concentration go higher. The yield stresses in the range of $0.5\~5\%$ agar-agar solution were $0.09\~1.21\;dyne/cm^2\;at\;80^{\circ}C,\;0.12\~5.29\;dyne/cm^2\;at\;60^{\circ}C\;and\;4.84\~58.37\;dyne/cm^2\;at\;50^{\circ}C$.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.209-214
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• 2014

In this paper, the rheological behaviors and non-Newtonian characteristics of maltenes which is effected by hydrocarbon solvent type, solvent mixing ratio, temperature and shear rate was measured and compared with oil sands bitumen. Maltenes was made by SDA (solvent deasphalting) method from oil sands bitumen. Oil sands bitumen had apparent viscosities of $800{\sim}150000mPa{\cdot}s$ measured at a shear rate of $50sec^{-1}$ in the range of $25{\sim}85^{\circ}C$ and showed yield stress of 0.1~0.3 Pa at the temperatures below $35^{\circ}C$. All the oil sands bitumen and maltenes exhibited a shear-thinning, i.e. pseudoplastic behavior and apparent viscosity of maltenes decreased with decreasing carbon numbers of hydrocarbon solvent. The change in apparent viscosity with temperature could be described by the simple Guzman-Andrade equation, and maltene viscosities were decreased as the mixing ratio of n-pentane was raised. Also, all maltenes approached to Newtonian fluid as temperature were increased. the degree of pseudoplasticity was enhanced with decreasing carbon number of solvent.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.742-748
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• 1989

Rheological properties of gelatinized millet starch dispersions were evaluated. Gelatinized nonwaxy and waxy millet starch dispersion were typical pseudoplastic fluids. At constant shear rate, gelatinized waxy millet starch dispersion showed higher shear stress than nonwaxy millet starch dispersion. Flow behaviours of gelatinized nonwaxy and waxy millet starch dispersion were well fitted to Herschel-Bulkley equation and flow behaviour index (n) and consistency index (K) were strongly concentration dependent. There was a linear relationship between concentration of gelatinized starch dispersion and square root of yield stress. The concentrations of gelatinized nonwaxy and waxy millet starch dispersion where yield stresses become zero were estimated as 2.19 and 1.69%, respectively. Pseudoplastic constant (m) approaches to a constant value in each type of millet starch when the concentration of gelatinized starch dispersion was increased. As the measuring temperatures increase, n value was increased, whereas, K value was decreased. The activation energies of gelatinized nonwaxy and waxy millet starch dispersion were 2.89 and 3.18kcal/mol, respectively.