• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.353-356
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• 2002

In this study, the clay samples collected in the area Mokpo carry out laboratory soil test. Under three different curing $temperature-20^{\circ}C,\;50^{\circ}C,\;80^{\circ}C$ and 4 terms of curing day -1day, 7days, 14days, 40days for each, the remolded and reconsolidated samples had been made. To find out an aging effects and geotechnical characteristics between undisturbed samples and reconsolidated samples, laboratory tests were preformed. In the results, it was found that mechanical properties of undisturbed natural samples were similar to high temperature reconsolidation clay. The curing temperature influence on simulating aging effect more than the curing day does and the best curing condition are $80^{\circ}C$, 27days.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.338-343
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• 2011

In this paper, the FT-IR, conductivity and flow electrification phenomena of Vegetable oils were discussed. Vegetable oil has high flash point and eco-friendly properties compared to conventional mineral oil. Accelerated aging transformer oil samples produced in the oven at 140[$^{\circ}C$] for 500 hours, 1000 hours, 1500 hours, 2000 hours. Serial device to measure the flow electrification phenomena was designed and fabricated. Pico ammeter and the Labview data measurements were utilized. The effects of Temperature and antistatic agent on fluid flow electrification were investigated. Both Mineral and vegetable oil showed similar trends for temperature change. The polarity reversal occurred in mineral oil with antistatic agent above 10 ~ 30[ppm] and in vegetable oil with antistatic agent above 5[ppm].

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.103-110
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• 2019

Cu-Zn-Al catalysts were prepared via co-precipitation method for low-temperature water-gas shift (LT-WGS) reaction under practical reaction condition. Aging time was systematically changed to find optimum point for LT-WGS under practical condition. The Cu-Zn-Al catalyst aged for 72 hours showed the highest CO conversion within low-temperature range as well as very stable catalytic activity for 200 hours despite the practical reaction condition.

• Food Science of Animal Resources
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• v.36 no.3
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• pp.343-351
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• 2016

The objective of this study was to evaluate the effects of a short-term/extreme temperature abuse (STA) on color characteristics and oxidative stability of aged beef muscles during simulated retail display. Two beef muscles (longissimus lumborum, LL and semitendinosus, ST) were aged for 7 (A7), 14 (A14), 21 (A21), and 28 d (A28), and further displayed at 2℃ for 7 d. The STA was induced by placing steak samples at 20℃ for 1 h on the 4th d of display. Instrumental and visual color evaluations, ferric ion reducing capacity (FRC) and 2-thiobarbituric acid reactive substances (TBARS) assay were performed. Initially, redness, yellowness and hue angle of all beef muscles were similar, regardless of aging time before display (p>0.05). An increase in postmortem aging time increased lipid oxidation and caused a rapid discoloration after STA during display (p<0.05). ST muscle was more sharply discolored and oxidized after STA, when compared to LL muscle (p<0.05). The FRC value of beef muscles was decreased after 7 d of display (p<0.05). The results from the current study indicate adverse impacts of postmortem aging on color and oxidative stabilities of beef muscles, particularly under temperature abusing conditions during retail display. Thus, developing a specific post-harvest strategy to control quality attributes in retail levels for different muscle types and aging conditions would be required.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.10 no.1
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• pp.1-6
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• 2004

Amount of residual ink solvent on the packaging materials from Korea, Japan and Europe was measured and compared. The amount of packaging materials from Korea was much higher than that of Japan and Europe. To reduce the residual amounts of ink solvent, aging condition of printed packaging materials including aging time and temperature was modified and evaluated. Aging with high temperature and short time ($60^{\circ}C$ and 24 hours) was more effective for reduction of residual amount of ink solvent than that with low temperature and long time. To find out change of reduction pattern of residual amount of solvent according to plastic packaging material, several monolayer and multilayer packaging materials were selected. Among the monolayer packaging materials, the amount of EVOH and PET was lower than that of polyolefin plastic film including PE and PP. PP/EVOH/PET among the selected multilayer film showed the lowest amount of residual ink solvent on food packaging materials. Result of this research revealed that the residual amount of ink solvent can be reduced by proper selection of aging condition with and by appropriate application of mutilayer plastic film.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.110-116
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• 2002

At elevated temperature, very complex precipitations occur in STS316. To investigate the effect of the precipitation on mechanical properties in SIS316, tensile tests and fatigue crack growth tests were carried out at $650^{\circ}C$ using artificially degraded materials. The material degradation was simulated by aging for up to 20000 hrs. at $750^{\circ}C$, which is equal to 179000hrs (about 20yrs) of service life at $650^{\circ}C$, after conducting solution treatment for 20 min. at $11300^{\circ}C$. The result of the hardness test and the tensile test showed that both properties are closely related to the mean free distance of carbides. Also, from the results of fracture tests at $650^{\circ}C$, ${\triangle}K_{th}$, after values were found to decrease as aging time and microstructure, as the volume fraction of $\sigma$ phase increased.

• Elastomers and Composites
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• v.44 no.4
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• pp.397-400
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• 2009

Ozone caused the crack on the surface of a rubber article by oxidation of double bond at room temperature. Wax migrates to the surface of a rubber article and makes a physical barrier to prevent process of ozonation. We investigated change of molecular weight distribution of waxes in unfilled NR, SBR, and BR vulcanizates before and after aging at room temperature for 6 months. Migration and evaporation behaviors of wax in a rubber article at ambient conditions help understand a role of wax as an antidegradant and appearance contamination of a rubber article. The relative intensity distribution of n-alkanes of the NR specimen after the aging was shifted to higher molecular weight compared with the relative intensity distribution before the aging, while those of the SBR specimen before and after the aging did not show a big difference.

• Elastomers and Composites
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• v.22 no.2
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• pp.109-120
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• 1987

In this study, as one of the developing ways of the functional elastomer, improvement of the functionality of CB-BR was attemped through stabilization. At first the stabilization effect of CB-BR and the concentration dependancy in CB-BR were determined. Then, triazine thiol derivative(BPTT) was synthesized by reacting p-aminodiphenylamine with cyanuric chloride. Further the functional mechanism and the effects of the antioxidants were investigated using BPTT together with other various antioxidants in liquid and solid states. The results obtained are as follows: 1) The aging of CB-BR depended on the concentration and temperature. Thus, at a low temperature of $50^{\circ}C$, the aging proceeded with gel formation; at high temperature above $100^{\circ}C$ and in above 4wt% concentration, the aging occured by the formation of gel. And in concentrations below that, the aging proceeds with a decomposition caused by oxygen attacked to elastomer molecules. 2) The effect of antioxidation of CB-BR in the liquid state was at it's best when the MBIZ and BPTT were used at $110^{\circ}C$, 4hrs after the oxidation. 3) The effect of antioxidation of CB-BR in the solid state was the best choice the simultaneous use of NDBC and BPTT at $50^{\circ}C$, 30days after the oxidation.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.157-165
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• 1997

The strength level of welded joint in room temperature and elevated temperature up to $600^{\circ}C$ was investigated in 250 and 300 grade 18% Ni maraging steel sheet welded with electron beam. The results obtained in this study are as follows; 1. Optimum welding heat input was 600J/cm in 1.0mm thickness and the room temperature tensile strength, joint efficiency of welded joint treated with optimum aging condition were found to be about 166kg/$mm^2$, 95% in 250 grade, 189kg/$mm^2$, 92% in 300 grade maraging steel sheet, respectively. 2. Tensile strength of welded joint in room temperature increased slightly by aging after repeated solution heat treatment, but the fracture mode showed a shear. 3. Joint efficiency at a temperature between $540^{\circ}C$and $600^{\circ}C$ found to be about 72% to 55%, but the joint efficiency exceeded about 90% below $300^{\circ}C$. 4. The fracture occurred in most weld metal, and the fracture surface showed a shallow dimple.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.523-524
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• 2007

Forest fire can give a serious damage to overhead conductors. Therefore, the definite understanding about aging behavior of burned conductor is very important in maintaining the transmission line safely. It is sure that the temperature of conductor itself will be affected by the distance apart from flame. From this point of a view, we monitored the conductor's temperature with distance from flame. As a result, the conductor's temperature decreased as the flame goes away from the conductor gradually. The temperature of conductor was reached up to 55~65% level of its atmospheric temperature. The detailed results will be presented in the text.