• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.4
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• pp.531-538
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• 2003

To elucidate the physicochemical change of Panicm miliaceum powders caused by irradiation and identify detection of irradiation, viscosity, TBA value, Hunter color and total viable count were measured after irradiation of Panicum miliaceum powder. Panicum miliaceum powders from Korea and China were irradiated at 0, 2.5, 5, 7.5, 10, 15 kGy using a $Co^{60}$ irradiator and stored for 9 months at $0^{\circ}C$ and $20^{\circ}C$. All samples resulted in decrease for viscosity and specific parameter values by increasing dosage at 50 rpm after irradiation. These values showed dose-dependent relationship (above $r^2$＝0.92) between non-irradiated and irradiated samples during storage. These results suggest that the detection of irradiated Panicum miliaceum at various doses is possible by using viscometric method during storage. Total viable count, TBA value and Hunter color were determined as assistant indices for the samples viscosity measured. Total viable count, TBA values showed dose-dependent relationship (2.5 ~15 kGy). The difference in viscosity along with total viable count, TBA values between non-irradiated samples little or some changed with the lapse of post-irradiation time, but was still distinguishable each other more than 6 months at $0^{\circ}C$ and $20^{\circ}C$ for Panicum miliaceum powders from Korea and China.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.113-118
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• 2006

In this work, we observed the changes in mass difference according to Al-foam's amount of Ca contents which depends on the viscosity control of fusion, quality of foamed addition, mixing, temperature tests. These are crucial influencing factors in determining foam-metal's size in the manufacturing process. In order to obtain the specimen, we changed the specific gravity from 0.2 to 0.3 for the study of the light weight, and obtained the optimal values of specific gravity, and then showed the mechanical characteristics of ultra-lightweight metal according to the changing mass. The optimal conditions for aluminum foam is when the addition of Ca content in $1.5wt\%~2.0wt\%$

• Bulletin of the Korean Mathematical Society
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• v.52 no.6
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• pp.1945-1962
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• 2015

This paper is mainly concerned with the formation of delta standing wave for the scalar conservation law with a linear flux function involving discontinuous coefficients by using the self-similar viscosity vanishing method. More precisely, we use the self-similar viscosity to smooth out the discontinuous coefficient such that the existence of approximate viscous solutions to the delta standing wave for the Riemann problem is established and then the convergence to the delta standing wave solution is also obtained when the viscosity parameter tends to zero. In addition, the Riemann problem is also solved with the standard method and the instability of Riemann solutions with respect to the specific small perturbation of initial data is pointed out in some particular situations.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.173-181
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• 2003

Physicochemical changes in corn starch caused by irradiation were investigated, and irradiated samples were identified. Viscosity, TBA value, Hunter color, and total viable count were measured after irradiation of corn starch. Corn starches from Korea and China were irradiated at 0, 2.5, 5, 7.5, 10, and 15 kGy using a $Co^{60}$ irradiator and stored for 9 months at $0^{\circ}C$ and $20^{\circ}C$. Viscosity and specific parameter values decreased in all samples with increasing irradiation dosage at 50 rpm, showing a dose-dependent relationship $(above\;R^2=0.80)$ between non-irradiated and irradiated samples during storage. These results suggest that detection of irradiated corn starches is possible using viscometric method during storage. Total viable count, TBA value, and Hunter color were determined as supplemental indices for measuring viscosities of samples. Total viable count and TBA values showed dose-dependent relationship $(2.5{\sim}15 kGy)$. Differences in viscosity and total viable count, and TBA values among non-irradiated samples showed little changes with the lapse of post-irradiation time, but were still distinguishable for more than 6 months at $0^{\circ}C$ and $20^{\circ}C$ for corn starches from korea and China.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.365-370
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• 2010

In this study, we carried out the evaluation of EPDM(Ethylene Propylene Diene Monomer) reclaimed rubber mixing with natural rubber at various mixing ratio to reuse as rubber filler. The scorch time and moony viscosity was analyzed to evaluate the effect of cure behavior. And also, we analyzed the tensile strength, the elongation at break and cure time to evaluate the variation of cure behavior. As the results, the scorch time and optimal cure time was decreased according to the increasing of EPDM reclaimed rubber. However, the moony viscosity was increased at each mixing ratio. In case of the added EPDM reclaimed rubber was 20 phr(parts by weight per 100 parts by weight of rubber), the hardness and specific gravity was increased a little. The hardness and specific gravity was increased in rapidly under 40 phr of the added EPEM reclaimed rubber. The tensile strength and elongation at break of the compound of natural and EPDM reclaimed rubber was rapidly decreased compared with its natural rubber when the ratio of adding EPDM reclaimed rubber was over 40 phr.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.640-645
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• 1995

Job's-tears(Coix lachryma-jobi L. var. Ma-yuen Stapf) seeds were processed to flakes by soaking, heat treatment, intermediate-moisture drying, flaking, drying, and cooking. Some functional properties of job's-tears flakes subjected to varing degree of heating were characterized by specific volume, texture, water absorption index(WAI), water solubility index(WSI), and viscosity. As degree of gelitinization increased within the intermediate range of $60{\sim}70%$, steam-cooked Job's-tears demonstrated appropriate rheological properties for further processes, resulting in increased specific volume and decreased breaking strength. However, excessive heat treatment rendered Job's-tears undesirably sticky for flaking, which caused adverse effects on the functional properties of flakes such as specific volume and breaking strength. Increasing steaming time$(5{\sim}30\;min)$ caused an increase in WAI and WSI values. Apparent viscosity of powdered flakes was increased with the extent of gelitinization as a function of heat processing. Viscosity of powdered flakes determined using the amylograph increased with the degree of heating applied to Job's-tears at low pasting temperatures, accompanied by a decrease in maximum viscosity as the pasting temperature increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1082-1087
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• 2001

A study was carried out to establish the detection method for irradiated cereals. Starchs were ground and irradiated at 2.5, 5.0, 7.5, 10 and 15 kGy using a Co-60 irradiator. The viscosities decreased in all samples by increasing irradiation dose. The viscosity of the potato, corn and sweet potato from Korea dropped from 35.00$\pm$ 0.34, 11.86$\pm$0.86 and 14.02$\pm$0.62 in the control to 11.38$\pm$0.92, 2.98$\pm$0.80 and 2.74$\pm$0.80, respectively, in the samples irradiated at 15 kGy. These trends were similar to samples from China. Regression expression and coefficients of viscosity of potato, corn and sweet potato starch from Korea were 0.97 (y=-4.6197x+38.284), 0.88 (y=-1.5146x+12.023) and 0.88 (y=-1.5146x+12.023), respectively, those of viscosity of starches from China were 0.69 (y=-28.849x+152.25), 0.81 (y=-3.38x+20.56) and 0.88 (y=-2.668x+18.505) at 50 rpm. All samples resulted in a decrease in specific parameter by increasing rpm after irradiation. Parameter values showed dose-dependent relationship between unirradiated and irradiated samples and indicated that all values of unirradiated samples were higher than the those of irradiated ones. These results suggest that the detection of irradiated potato, corn and sweet potato starch at various irradiation doses is possible by the viscometric method.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.67-75
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• 2007

As a part of abating the formaldehyde emission of urea-formaldehyde (UF) resin adhesive by lowering formaldehyde to urea (F/U) mole ratio, this study was conducted to investigate properties of UF resin adhesive with different F/U mole ratios. UF resin adhesives were synthesized at different F/U mole ratios of 1.6, 1.4, 1.2, and 1.0. Properties of UF resin adhesives measured were non-volatile solids content, pH level, viscosity, water tolerance, specific gravity, gel time and free formaldehyde content. In addition, a linear relationship between non-volatile solids content and sucrose concentration measured by a refractometer was established for a faster determination of the non-volatile solids content of UF resin. As F/U mole ratio was lowered, non-volatile solids content, pH, specific gravity, water tolerance, and gel time increased while free formaldehyde content and viscosity were decreased. These results suggested that the amount of free formaldehyde strongly affected the reactivity of UF resin. Lowering F/U mole ratio of UF resin as a way of abating formaldehyde emission consequently requires improving its reactivity.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.101-106
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• 1999

Fiber reinforced plastic composites is widely used to make be lightening of aircraft and automotive owing to having high specific strength and specific modulus. And it is very important to know a charge shape in order to have good products in the compression molding. In particular, the product such as a bumper beam is composed of the random and unidirectional composite mats. Its deformation and charge shape are very different by stack type of random and unidirectional mats. In this paper, the characteristics of flow fronts such as a bulging phenomenon for step-type random/unidirectional composite mats and slip parameters are studied numerically. And the effects of viscosity ratio and stack type on the mold filling parameters are also discussed.

• Proceedings of KOSOMES biannual meeting
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• 2001.10a
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• pp.17-24
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• 2001

The sludge oils were produced necessarily in the ships operation, so that it will be the best way to manage the sludge oils inside ship itself from a viewpoint of the prevention of marine oil pollution from ship. The present study deal with the ultrasonic breaking systems which recycle the sludge oil from ships into usable oil to be burnt. The first place, experimental studies were carried out to investigate the homogenizing effect of the marine oils by repeated vibration of ultrasonic transducer. Variation of the properties(viscosity, specific gravity and pH) and the matrix structures for the environment of various marine oils were interpreted to analyze the breaking, dispersion effects by cavity. The experimental results can be useful to the development of sludge oil disposing systems.