• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.489-497
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• 2004

Objective: The purpose of this study was to investigate the viscoelastic properties related to handling characteristics of composite resins, Methods: A custom designed vertical oscillation rheometer (VOR) was used for rheological measurements of composites. The VOR consists of three parts: (1) a measuring unit, (2) a deformation induction unit and (3) a force detecting unit, Two medium viscous composites, Z100 and Z250 and two packable composites, P60 and SureFil were tested. The viscoelastic material function, including complex modulus $E^{*}$ and phase angle ${\delta}$, were measured. A dynamic oscillatory test was used to evaluate the storage modulus (E'), loss modulus (E") and loss tangent ($tan{\delta}$) of the composites as a function of frequency ($\omega$) from 0.1 to 20 Hz at $23^{\circ}C$. Results: The E' and E" increased with increasing frequency and showed differences in magnitude between brands. The $E^{*}s$ of composites at ${\omega}{\;}={\;}2{\;}Hz$, normalized to that of Z100, were 2.16 (Z250), 4,80 (P60) and 25.21 (SureFil). The magnitudes and patterns of the change of $tan{\delta}$ of composites with increasing frequency were significantly different between brands. The relationships between the complex modulus $E^{*}$, the phase angle ${\delta}$ and the frequency \omega were represented by frequency domain phasor form, $E^{*}{\;}(\omega){\;}={\;}E^{*}e^{i{\delta}}{\;}={\;}E^{*}{\angle}{\delta}$. Conclusions: The viscoelasticity of composites that influences handling characteristics is significant different between brands, The VOR is a relatively simple device for dynamic, mechanical analysis of high viscous dental composites. The locus of frequency domain phasor plots in a complex plane is a valuable method of representing the viscoelastic properties of composites.

• The Korean Journal of Food And Nutrition
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• v.14 no.6
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• pp.585-590
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• 2001

The purpose of this study was to examine physical properties of the addition of Plantago powder on bread flour and dough fheology of white pan bread. Four levels(0.3, 0.6, 0.9 and 1.2%) of each Plantago powder with bread flour were tested for their effects in dough mixing using rapid visco analyzer, alveogram, farinogram and sensory test. Addition of Plantago powder(0.3, 0.6 and 0.9% ) showed almost same tendency on the initial pasting temperature but 1.2% increased it. Increment of Plantago powder showed increment of peak viscosity and final viscosity, L(extensibility) and G(swelling index) value in alveogram showed decrement with increasing Plantago powder. In farinogram the use of Plantago powder increased consistency and water absorption but decreased development time and stability. White pan bread using Plantago powder had higher value of Max. G and gardeness in rheometer than without using it. Sensory evaluation of white pan bread with 0.6% Plantago powder had the highest score.

• Korean journal of food and cookery science
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• v.7 no.1
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• pp.53-59
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• 1991

The purpose of this study is to investigate textural characteristics of egg solution coagulated with steamer and microwave oven, and egg solution diluted various concentration of it with water or milk. Textural Characteristics of the samples were evaluated by the Sensory test and Rheometer. The results obstained were as follow; 1. Rheometer measurement indicated that the thicker is concentration of egg solution, the harder is samples 2. In sensory evaluation on the various concentration of egg solution, the panels on the overall quality showed the most favorite tendency that the sample diluted with 50% of water and the one with 70% of milk in use steamer; the sample diluted with 30% of water and the one with 70% of milk in use microwave oven.

• Elastomers and Composites
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• v.45 no.2
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• pp.87-93
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• 2010

The fire resistive materials are used to resist from fire accidents in the building. In this study silicone rubber/inorganic flame retardant composites were prepared by mechanical stirring method, using aluminium trihydroxide(ATH, $Al(OH)_3$) and magnesium dihydroxide(MDH, $Mg(OH)_2$) as synergistic fire-resistant additives. The thermal properties of the fire resistant composites were characterized by thermogravimetric analysis(TGA). In addition, rheological properties were observed by rheometer and fire-resistant properties were tested by gas torch. Through this study, we realized that the silicone rubber containing ATH, MDH increased the performance of fire-resistance.

• Elastomers and Composites
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• v.48 no.1
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• pp.18-23
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• 2013

Nylon 12 elastomer was slightly crosslinked in molten state by the addition of small amount of dicumyl peroxide (DCP) as a crosslink agent and triallycyanuate (TAC) as a co-agent during melt compounding at $160^{\circ}C$ in an internal mixer. The effect of the peroxide crosslinking on mechanical, dynamic mechanical and rheological properties of the nylon 12 elastomer was investigated by means of tensile testing, dynamic mechanical analysis (DMA) and small amplitude oscillating rheometer, respectively. With modification, there is an improvement in tensile modulus and Young's modulus with decease in elongation at break. DMA results for peroxide modified nylon 12 elastomers demonstrated that the glass transiaiton temperature of PTMG segment shifted to higher temperature and the storage modulus remained constant above the melting temperature of nylon 12 segments. Melt rheological studies revealed that the peroxide modified nylon 12 elastomer exhibited a more solid like behavior and stronger shear thinning behavior compared to neat nylon 12 elastomer, which was more prominent at higher TAC content in the polymer matrix. The peroxide modified nylon 12 elastomer exhibited good elastic recoverability and improved mechanical properties without sacrificing melt processibilty, and especially the service temperature range increased as compared to neat nylon 12 elastomer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.4028-4032
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• 2013

Recycling method for pyrolyzed carbon black from pyrolysis process of waste tires is needed. Carbon black from pyrolysis of waste tires was used to modify and improve the permanent deformation properties of asphalt binder. 0%, 5%, 10%, 15% and 20% of pyrolyzed carbon black was mixed. Couple of laboratory tests, such as softening point, flash point test, rotational viscometer test and dynamic shear rheometer test, were carried out. The use of pyrolyzed carbon black incresed the softening point, rotational viscosity at 135oC, and resistance of permanent deformation.

• Korean journal of food and cookery science
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• v.18 no.6
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• pp.567-572
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• 2002

The effects of adding mulberry leaves powder, yellow soybean powder(YSP), and mugwor powder(MP) for the preparation of mungbean starch gels(MSG) were studied. MSG with above additives were analysed for proximate composition. sensory evaluation, chromaticity, and rheometric properties. In the proximate composition test, the moisture content was the highest in the MSG with 0.5% MP, and the crude protein content war the highest in MSG with 1.0% YSP. In the sensory evaluation, MSG with various additives showed higher values than control. Whereas MSG with 0.5% additives showed a high value in hardness, control gels showed high values in the gumminess and brittleness in the measurement with a rheometer.

• Elastomers and Composites
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• v.17 no.4
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• pp.215-225
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• 1982

The purpose of this study is to get comparitive results on the combined accelerator systems comprised of MBT, MBTS, DPG and CBS with TMTD, TMTM and Zn-MDC to SBR compound. Vulcanization characterstics and physical properties of the combined accelerators have been studied by means of the Mooney viscometer, the Monsanto disc rheometer, tensile testing machine, aging chamber and so on. According to the test results, DPG, MBT and Zn-MDC system have show faster Mooney scorch time and optimum cure time than other systems. The Vulcanizate comprise of DPG, MBT and TMTD accelerator system has taken adventage of tensile strength, elongation, 100% modulus, resilience, compresion set.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.237-243
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• 1995

"Woomegi Dduck" is one of Korean traditional pan fried rice cake made from glutinous rice by Tack-joo(rice wine) or boiling water. The optimum conditions for the preparation of "Woomegi Dduck" were investigated. The Hardnes, Cohesiveness, Gumminess, Chewiness, Adhesiveness of "Woomegi Dduck" added Tack-joo or boiling water measured by Rheometer, didn′t have significant difference between samples. The result of color test was L-Value, a-Value, b-Value and E Value of Woomegi Dduck added boiling water and 20％ rice flour were high. The best recipe of Woomegi Dduck was glutinous rice flour 50g, rice flour 20g, Tack-joo 30$m\ell$, or boiling water 25$m\ell$, sugar 10g.

• Journal of Pharmaceutical Investigation
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• v.15 no.3
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• pp.121-129
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• 1985

Influences of various waxes on the consistency of cream was investigated by inspections through microscope, rheometer and sensory test. Fatty acids, higher fatty alcohols, hydrocarbons, and some of natural waxes were used in this experiment. Most above waxes showed good state of emulsion at low concentration, but at higher concentration $(7.0{\sim}8.0%)$, they showed not only an unstable emulsion state but also a critical point of content in consistency. At this critical point of content, the consistency of w/o type cream was increased irregularly. So, it could be identified that consistency of a w/o type cream was strongly dependent on kinds and contents of waxes in continuous phase.