• Journal of Magnetics
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• v.19 no.4
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• pp.345-348
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• 2014

Magnetorheological suspensions (MRSs) are smart materials that have the potential to revolutionize several industrial sectors because of their special rheological behaviors. In this paper, MRS, based on carbonyl iron (CI) microparticles that were dispersed in silicone oil with oleic acid, were prepared. We showed that the electroconductibility of MRS was significantly influenced by the intensity of the external magnetic field that was applied. The resistance value can vary from infinite to below $300{\Omega}$ after applying an external magnetic field. The results indicated that this MRS had the property of magnetic-field-tuned insulator to conductor transition. This system has potential applications in controllable MRS electrical devices.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.673-678
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• 1997

Associative acrylic thickeners were prepared by emulsion copolymerization using nonionic vinyl surfactant esters as an associative macromonomer and their rheological properties were investigated. The thickening efficiency was shown to depend on the chain length of therminal hydrophobe and degree of ethoxylation of VSE. increasing the content of VSE enhanced the efficiency of the resulting polymers as a thickener. It was attributed to the intermolecular association of terminal hydrophobes of associative thickener in aqueous solution. The chain transfer agent caused to reduce the molecular weight of associative thickener, resulted in decrease of thickening efficiency.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.1
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• pp.37-42
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• 2011

The rheological properties of the aqueous solution of scleroglucan industrially produced by Sclerotium rolfsii at concentrations ranging from 0.1 % to 2 % (w/w) were determined by using brookfield viscometer and rheometer. Gel matrices of scleroglucans were stable over a wide range of pH and ionic strength in the aqueous medium. In the oil dispersion with phytosqualane in oil phase and three kinds of thickening agent in aqueous phase, scleroglucan showed the highest dispersion properties. The synergistic effect between scleroglucan and locust bean gum was also examined. The highest viscosity was obtained for the solution mixture at scleroglucan/locust bean gum weight ratio of 5 : 5. The results of this study suggest the potential of scleroglucan as thickner for a wide variety of cosmetic formulations.

• The Korean Journal of Food And Nutrition
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• v.19 no.2
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• pp.207-218
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• 2006

This study was designed to investigate the possible utilization of Ligularia stenocephala as a source of functional ingredients in white bread. In terms of color values, as more Ligularia stenocephala leaf powder was added, 'lightness,' 'redness,' and 'yellowness' decreased in the crust, while in the bread crumb 'lightness' and 'yellowness' decreased, but 'redness' increased. When 5.0%, 7.5%, or 10.0% Ligularia stenocephala leaf powder was substituted for an equivalent amount of strong flour, the ratio of the volume and specific volume of white bread decreased while its weight increased. In the texture measurements for the white breads, the hardness decreased slightly with the addition of 2.5% Ligularia stenocephala leaf powder, but increased with the addition of 5.0%, 7.5%, or 10.0% Ligularia stenocephala leaf powder. The addition of the Ligularia stenocephala leaf powder also increased the springiness and gumminess of the white bread. The highest sensory scores for color, flavor, taste, texture, and overall acceptance for both the student group and the baker group were obtained from white bread with 5.0% Ligularia stenocephala leaf powder. The highest sensory scores for the housewife group for taste, texture, and overall acceptance were obtained from control bread. Through the results of these experiments, we conclude that the highest quantity of Ligularia stenocephala leaf powder content should be no more than 5.0% when making bread with added Ligularia stenocephala leaf powder.

• Food Science of Animal Resources
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• v.20 no.4
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• pp.264-271
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• 2000

정육 대체물질의 첨가에 따른 효과를 살피기위해 건조 소 혈장 단백질을 단계별로 높이면서 제조한 비엔나 소시지의 물성적 특성 드을 경시적으로 고찰 비교하였다. 수율은 방냉후 축정된 것으로 81.60~84.88% 범위이며 대조구와 D-2, D-3간의유의적인 차이를 보였다. (P<0.05). 조직의 부분적인 연화 정도는 대조구에 비해 비교구에서 소 혈장 단백질의 첨가수준이 높은 시럼구에서 높았고 열 매체에 의한 영향은 boiled>microwave>fried의 순이 었다. 겔강도와 경도는 대조구와 비교구 사이, 수직 측정과 수평 측정 사이, 저장기간에 따라 유의적인 차이를 볼 수 있었다.(P<0.05), 전단 강도는 수직측정보다는 수평측정이 높은 수치를 보이고 initial에서 대조구와 비교구 사이 차이가 적게 나타나나 40일 저장한 것에서는 차이 값이 높았다. 전단 경도에 있어서는 initial 에 비해 10일 , 40일 에는 감소함을 보이나 수칙측정과 수평측정간 차이를 보였다 L 값은 시험구간과 저장기간에 의해서도 안정함을 보이며 a값은 대조구에 비해 비교구에서 감소함을 보이나 10일 40일 저장된 것에서 증가함을 보이고, b값은 시험구간 사이 비슷한 수준이나 저장기간에 따라서는 감소를 보였다. 기호성 평가에서 색상, 풍미, 조직감은 시험 제품 사이에 차이를 보이고 저장기간에 의해서는 약간의 감소를 보이며 천제적인 수용도는 대조구가 가장 높은 점수였다.

• The Korean Journal of Community Living Science
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• v.23 no.1
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• pp.51-59
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• 2012

This study was conducted to investigate the rheological properties of mulberry powder on the weak flour using color, Rapid Visco Amalyzer(RVA), farinogram, alveogram. The lightness(L value) and yellowness(b value) decreased and the redness(a value) increased with increment of mulberry powder content. On the RVA data, the weak flour with 1% of mulberry powder showed the highest initial pasting temperature and peak viscosity, while the addition of mulberry powder reduced final viscosity. On the farinogram data, the consistency of the flour containing mulberry powder was decreased with increments of mulberry powder. This meant that mulberry powder could weaken the batter. Water absorption of the samples with mulberry powder was decreased more than the control. The development time of flour with mulberry powder was also decreased more than control, but the differences were not significant. The stability of the flour with adding mulberry powder was decreased. The Pmax value of the flour was decreased significantly by adding mulberry powder. Extensibility and swelling index were both increased, but there were no significant differences.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.791-794
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• 2008

MRE(Magneto-rheological Elastomer) is a material which shows reversible and various modulus in magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb broader frequency range of vibration. These characteristic phenomena result from the orientation of magnetic particle (i.e., chain-like formation) in rubber matrix. In this study, NR was used as a matrix in order to manufacture MREs. Magnetic reactive powder(MRP), having rapid magnetic reaction, was selected as a magnetic particle to give magnetic field reactive modulus. The mechanical properties of manufactured MREs were measured without the application of magnetic field. The results showed that the tensile property and resilience were decreased while the hardness was increased with the addition of CIP. The analysis of MR effect was carried out by FFT analyzer with various magnetic flux. As the addition of MRP and magnetic flux increased, increment of MR effect was observed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.5
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• pp.665-671
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• 2020

The chemical and rheological properties of fucoidan and alginate prepared from different parts of Undaria pinnatifida (sporophyll, frond, stipe) were investigated. The algal materials were extracted with HCl (pH 2.0, 3 h at 70℃) to prepare fucoidan, and the remaining solid was continuously re-extracted with Na₂CO₃ (pH 10.0, 70℃, 3 h) to prepare alginic acid. The fucoidan and alginic acid contents in the sporophyll, frond, and stipe were 11.14%, 3.84%, and 1.73% and 22.04%, 37.14%, and 31.74%, respectively. The content of fucoidan and alginate depends on the part extracted. The fucoidan extracted from the sporophyll mainly consists of fucose and galactose, but the fucoidan extracted from frond and stipe contains mannose in addition to fucose and galactose. Fourier-transform infrared spectroscopy analysis of fucoidan and alginate suggests the presence of sulfate groups (1261 and 840 cm^-1) and carboxyl groups (1626 and 1419 cm^-1), respectively. Alginate solutions (5%) had a low viscosity of 10.84-31.63 mPa·s. The activation energies of fucoidan and sodium alginate were 14.45-18.38 kJ/mol and 18.61-22.06 kJ/mol, respectively. The D-mannuronic acid/L-guluronic acid (M/G) ratios of alginate showed a relatively high (frond, 3.72; stipe, 2.88; and sporophyll, 1.80).

• Proceedings of the Korean Society of Rheology Conference
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• 2002.05a
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• pp.25-27
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• 2002

In this study we investigated the reaction kinetics by a convenient but useful method-rheology to characterize the interface between two immiscible blends with a Reactive compatibilizer. Also, we made an attempt to correlate changes of interface roughness with rheological properties. The blend systems employed in this study was mono-carboxylated polystyrene (PS-mCOOH) and an poly(methyl methacrylate-ran-glycidylmethacrylate) (PMMA-GMA). PS-mCOOH was synthesized by an anionic polymerization and PMMA-GMA by a free radical polymerization. We prepared two plates of each polymer using compression molding with a smooth surface molder, then put one upon another. As soon as these two plates welds together inside a rheometer under nitrogen environment, the torque and moduli were obtained with reaction time at different temperatures. Through the analysis of this modulus change with reaction time, we estimated interfacial reaction and roughening. The increment of modulus in initial state can be correlated to the extent of reaction. We obtained the reaction kinetic constant by fitting appropriate kinetic equation into experimental data. We also showed that increment of modulus in later state was due to by roughened interface.

• Korea-Australia Rheology Journal
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• v.19 no.2
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• pp.75-80
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• 2007

The slotted plate technique has previously been shown to be a successful method for directly measuring the static yield stress of suspensions. In this study, we further establish the usefulness of the slotted plate device as a rheometer especially at low shear rates, taking advantage of the extremely low speeds of the slotted plate technique. Newtonian fluids, a shear thinning fluid, and yield stress fluids were tested using the slotted plate device and the results were compared with those from a commercial rheometer using different standard flow geometries. The relationship between the stress on the plate and the viscosity for the slotted plate device obtained by dimensional analysis (drag) predicts a linear relationship between the force at the plate and the plate speed, consistent with the experimental data. The slotted plate device can measure viscosities at very low shear rates. The apparent viscosity - shear-rate data obtained from the slotted plate device are complementary to those obtained using a commercial rheometer. That is : the slotted plate can measure viscosity in the shear rate range $10^{-7}<\dot{\gamma}<10^{-3}\;s^{-1}$, while the commercial rheometer measures viscosity at shear rates higher than $10^{-3}\;s^{-1}$.