• Journal of Animal Science and Technology
• /
• v.60 no.9
• /
• pp.23.1-23.9
• /
• 2018

Background: Aging trials are conducted to determine characteristics associated with dry- and wet-aging processes of beef from delivered cows grown in Okinawa, i.e., dams that have finished giving birth (Okinawan delivered cow beef). Changes in free amino acids, hardness, and other factors were analyzed in round of Okinawan delivered cow beef during dry- and wet-aging processes along with a comparison with characteristics of beef imported from Australia. Results: Functional amino acids did not increase during both dry- and wet-aging processes. However, proteinogenic amino acids increased significantly (P < 0.05) and hardness tended to decrease during both dry- and wet-aging processes. On comparison between dry- and wet-aging processes by analysis of variance, drip and cooking losses were significantly lower during the dry-aging process than during the wet-aging process. However, there was no significant difference in free amino acids or hardness in this comparison. Conclusion: There was no significant difference between dry- and wet-aging methods for all studied variables related to free amino acids or hardness in this study.

• Journal of the Korean Society of Safety
• /
• v.35 no.5
• /
• pp.22-29
• /
• 2020

In this study, combustion and smoke release characteristics of a non-class 1E cable for nuclear power plants were investigated according to aging period. The aging was reproduced through an accelerated aging method for interval of 10 years :10, 20, 30 and 40 year, which was applied the Arrhenius equation. The cable was subjected to accelerated aging. In order to understand combustion and smoke release characteristics, the cone calorimeter test was performed according to the standard code of KS F ISO 5660-1. Heat release rate, mass loss rate, average rate of heat emission and smoke production rate were examined through cone calorimeter test. Fire performance index, fire growth index and smoke factor were derived from test results for the comparison of quantitative fire risk. When comparing the fire performance index and the fire growth index, the early fire risk tends to decrease as aging progresses, which might be attributed from the fact that the volatile substances of cables were evaporated. However, when comparing the heat release rate, average rate of heat emission and mass loss rate, which represent the mid and late periods of the fire risk, the values of accelerated aging cables were much higher than those of non-aged cable, which signifies the unstable formation of the char layer resulted in the change in the performance of flame retardants. In addition, the results from the smoke characteristics show that the accelerated aging cables were lager than the non-aged cables in terms of overall fire risk. These results can be used as baseline data when assessing fire risk of cables and establishing fire safety code for nuclear power plants.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.601-604
• /
• 2001

22.9 kV CV power cable is very important factor of underground distribution power line. Cyclic aging for 14days is performed to remove a large amount of the volatiles found in freshly manufactured cable. In this paper, we examined AC breakdown characteristics of CV power cable before and after cyclic aging for 14days. As the result, even if there were some exceptions, the AC breakdown voltage before aging was lower than that after aging, but most of the results were that the AC breakdown voltage after aging was lower than that before aging.

• Proceedings of the KIEE Conference
• /
• 2005.07c
• /
• pp.2274-2276
• /
• 2005

Cyclic aging for 14days is performed to remove the large amount of the volatiles found in freshly manufactured cable. In this paper, we examined lightning impulse characteristics of power cable before and after cyclic aging for 14days. As the result, the breakdown voltage after aging was lower than that before aging, but the breakdown voltage after aging was higher than that before aging in TR CNCV-W $60mm^2$ power cable.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.4
• /
• pp.693-699
• /
• 2010

General transformer's life is known as paper insulation' life. If a transformer is degraded by these aging factors, it is known that electrical, mechanical and chemical characteristics for transformer's oil-paper are changed. When the kraft paper is aged, the cellulose polymer chains break down into shorter lengths. It causes decrease in both tensile strength and degree of polymerization of paper insulation. The paper breakdown is accompanied by an increase in the content of furanic compounds within the dielectric liquid. In this paper it is aimed at analysis on correlation between aging characteristics for insulating diagnosis of thermally aged paper. For investigating the accelerated aging process of oil-paper samples accelerating aging cell was manufactured for estimating variation of paper insulation during 500 hours at $140^{\circ}C$ temperature. To derive the results, it was performed analysis such as tensile strength(TS), depolymerization(DP), dielectric strength(DS), relative permittivity, water content(WC) and furan compound(FC) for aged paper. Also for analyzing correlation between insulating degradation characteristics, we used linear regression method. As as results of linear regression analysis, there was a close correlation between TS and DP. WC, FC. But dielectric strength was a weak correlation with aging time.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.05a
• /
• pp.210-213
• /
• 2007

In this study accelerated aging test cycle and equipment was developed for aging test of polymer housed surge arresters under domestic weather condition In order to investigate aging characteristics of polymer surge arresters electrical and chemical analysis of the arresters which are used for accelerated aging test and outdoor exposure test were conducted. Through the analysis the capability of the proposed method was verified and characteristics data were presented for maintenance of domestic arresters. Based on these results long term reliability assessment method was proposed for polymer housed distribution surge arresters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.1
• /
• pp.93-97
• /
• 2009

We analyzed voltage characteristics of toner particle type display according to particle layers and cell gap between two electrodes and ascertained the aging effects by measuring the response time of particles with and without aging process. The threshold/driving/breakdown voltage is proportional to layers of toner particles and cell gap and the response time at driving voltage is faster than that of threshold and breakdown voltage because of different q/m of color and black particles. The analysis of response time is a method of estimation of optical characteristics, driving voltage and particle lumping and these results are promoted by aging process. We use the laser and photodiode to measure response time and optical properties. It has not been studied and reported to analyze the relationship of response time, threshold/driving/breakdown voltage, lumping phenomena, cell gap, and aging process for toner particle type display.

• 전기의세계
• /
• v.14 no.3
• /
• pp.18-27
• /
• 1965

It is well known that the starting characteristics of the cold cathode type discharge tubes are irregular. We have two kinds of stabilization for starting characteristics of discharge tubes. Which are the aging test immediately after producing the tubes and the using characteristics. This paper was devoted primaliry to the empric study of relation between the aging and the manufacturing process. And then to stabilize the starting characteristics of discharge tubes by the irradiations of radio-isotope.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1948-1950
• /
• 2000

Polymeric composite insulators have been in use for outdoor insulation. However, our knowledge about their long-term performance in an outdoor environment is still very limited. Especially, these insulators are subjected to the environmental stress such as ultraviolet radiation, electrical stress, mechanical load, etc.. Hence, in this paper, we simulated the factors having influence on aging of polymer insulators using the combined aging test chamber. In order to evaluate an aging characteristics with time, we measured leakage current on these insulators to make out the degree of aging.

• Journal of Surface Science and Engineering
• /
• v.50 no.5
• /
• pp.380-385
• /
• 2017

Mechanical characteristics of the STS 304 which is heat resistance steel were investigated after artificial aging at $650^{\circ}C$ with 1,000 hours. Tensile test specimens and small test pieces were done artificial aging up to 1,000 hours in the high temperature atmospheric environment. The results present that as the aging time increased, tensile properties were deteriorated. In the case of failure mechanism, the configuration of the fractography presented drastic change from ductile to brittle with aging time. $M_{23}C_6$ carbide leading to the change of the mechanical properties and fracture mode of the aged STS 304 steel continuously precipitated along the grain boundaries of austenite microstructure.