• Proceedings of the KSME Conference
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• 2003.04a
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• pp.352-357
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• 2003

Creep tests for Titan were carned out using constant-load at $600^{\circ}C$, $650^{\circ}C$ and $700^{\circ}C$. Material constants necessary to predict creep life were acquired from the experimental creep data. And the applicability of Monkman-Grant(M-G) and modified M-G relationships was discussed. It was discovered the log-log plot of M-G relationships between the rupure time(tr) and he minimum creep rate(${\varepsilon}_m$) was conditional on test temperatures. The slop of m was 2.75 at $600^{\circ}C$ and m was 1.92 at $700^{\circ}C$. However; the log-log plot of modified M-G relationships between $t_r/\varepsilon_r$ and $\varepsilon_m$ was indpendent on stresses and temperatures. That is the slop of m' was almost 3.90 in all the data. Thus, change M-G relationships to creep life prediction could be vtilized more reasonably than that of M-G relationships for type Titan. It was divided that the constant slopes never theless of temperatures of practical stresses in the modified relationship were due to an intergranular break grown by wedge-type cauities.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.3
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• pp.285-293
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• 2005

This study was aimed at estimation of gas-particle partitioning of polychlorinated biphenyls (PCBs) in ambient air. The samples were collected at urban site in Japan from March 2002 to January 2003. The concentration of total PCBs (from 4 CB to 10 CB) and TEQ (Toxic equivalent) ranged from 62 to $247\;pg/m^3$ and from 2 to $14\;fgTEQ/m^3 $, respectively. The average contribution $(\%)$ of gas phase to total PCBs concentration was above $80\%$, which suggests that in the atmosphere PCBs predominantly existed in the gas phase. The weak correlations between total PCBs concentration and temperature was found. However this result was due to a typhoon during summer and raining during sampling period. The gas-particle partition coefficient (Kp) was obtained as a function of temperature. The partition ratio of gaseous and particulate phase PCBs can be estimated for an arbitrary temperature. The plot of gas/particle partition coefficient (log Kp) vs. sub-cooled liquid vapor pressure $(log\;P_L)$ had reasonable correlations for individual samples but the slope varied among the samples (coefficients of determination for log Kp versus log $P_L$ plot were> 0.76 $(p<0.0001)$, except for 3 samples). As a result, the variations in the slope among the sampling period may be due to change of temperature, raining during sampling period and wind in this study.

• Journal of Radiation Protection and Research
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• v.7 no.1
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• pp.23-33
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• 1982

The characteristic thermoluminescence responses of Teflon thermoluminescent dosimeters to radiations have been studied by the variation of radiation qualities as well as the high dose radiations. The change in the sensitivity of TLDs for different radiation qualities were studied through not only the photon energy dependence but also the change of supralinearity on the photon energy dependence, by exposing $^{60}Co$ gamma rays, the effective X-rays of 44keV, 69keV, 108keV, and thermal neutron of 0.04 eV. The results were as the following: The TL response of $T-CaSO_4$: Dy as a function of absorbed dose was linear up to about 5 Gy, and the response beyond 5Gy was supralinear for $^{60}Co$ gamma rays. The supralinearity of T-LiF-7 became noticeably apparent more than that of $T-CaSO_4$:Dy and also the lower the LET of radiation became the higher the supralinear effects were. No supralinearity appeared for the thermal neutron irradiations equivalent to 10Gy of $^{60}Co$ gamma rays. The relative sensitivities (Rs), which depended on the doses of $^{60}Co$ gamma rays to the TLDs of T-LiF-7 and T-$CaSO_4$:Dy could be, respectively, approximated to the following empirical formula fitted by the least square method: $$R_{LiF}=1.021-0.04581\;logD+0.402(logD)^2-0.405(logD)^3,\;\;5{\times}10^3{\geq}D{\geq}1(Gy)$$ $$R_{CaSO_4}=0.976-0.3241\;logD+0.262(logD)^2-0.298(logD)^3,\;5{\times}10^3{\geq}D{\geq}1(Gy)$$.

• Applied Biological Chemistry
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• v.49 no.2
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• pp.158-162
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• 2006

To determine freshness and quality change of tofu during storage, we manufactured a freshness indicator and monitored the surface pH, volatile basic nitrogen (VBN), thiobarbituric acid reacted substance (TBARS), total bacterial counts, and sensory evaluation. Tofu had a change in color of the freshness indicator after storage of 8 days at $4^{\circ}C$, and its pH and total bacterial counts reached 5.6 and 7.63 log CFU/g, respectively. VBN and TBARS values increased and reached the decay point at the time of color change of the freshness indicator. Sensory evaluation also indicated that samples were unacceptable by off-odor and decrease of firmness at day 8 of storage. These results suggest that a freshness indicator should be useful in determining expiration date of tofu products during marketing by indicating the microbial safety as well as sensory change.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.3-8
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• 1986

The investigation of the effect of solvent structure on the first-order solvolysis of cis-$[Co(en)_2ClNO_2]^+$ion has been extended to water + co-solvent mixtures where the co-solvents are glycerol, ethylene glycol, isopropyl alcohol and t-butyl alcohol. Rates of solvolysis have been evaluated by spectrophotometric method at temperature 25∼30$^{\circ}$C. The polarity of solvent has influence on the variation of rate constant. The non-linear plot of the rate constant in log scale versus $\frac{D-1}{2D+1}$ implies that change in solvent structure with composition plays an important role in determining the variation of rate constant. The linearity of the plot of the rate constant in log scale versus the Grundwald-Winstein Y factor confirms that the solvolysis is an Id-type process with considerable extension of the metal chloride bond in the transition state. In the Kivinen equation the slope of the plot of log k versus $log(H_2O)$ suggests that the solvolysis is also an Id-type process. The application of free energy cycle shows that the effect of solvent structure is greater in the transition state than in the initial state.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.245-252
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• 2011

The combined effects of 10 kJ/$m^2$ ultraviolet-C (UV-C) with 50 ppm aqueous chlorine dioxide ($ClO_2$) on the qualities of red chicory and pak choi were examined. After the treatment, the samples were stored at $4{\pm}1^{\circ}C$ for 7 days. The combined treatment of $ClO_2$/UV-C reduced the initial populations of total aerobic bacteria in the red chicory and pak choi by 2.64 and 2.55 log CFU/g, respectively, compared to those of the control. Also, the populations of yeast and molds in the red chicory and pak choi by combined treatment were reduced by 2.41 and 2.00 log CFU/g, respectively. In addition, after 7 days of storage the total aerobic bacteria populations in the red chicory and pak choi were reduced to 3.71 and 3.93 log CFU/g, compared to 6.31 and 6.62 log CFU/g for the control, resulting in a significant decrease. Hunter L, a, and b values of red chicory and pak choi were not significantly different among the treatments. Non-thermal treatment caused a negligible change in sensory evaluation. These results suggest that the combined treatment of 50 ppm $ClO_2$ with 10 kJ/$m^2$ UV-C can be useful for maintaining the qualities of red chicory and pak choi.

• Journal of Food Hygiene and Safety
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• v.38 no.1
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• pp.19-25
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• 2023

Addition of spice for inhibition of bacterial growth in ground chicken meat was investigated. The ground chicken meat approximately contained 72.98±0.15% moisture, 23.37±0.46% crude protein, 1.00±0.03% crude fat, and 1.90±0.03% ashes. Addition of rosemary showed the maximum bacterial inhibition, followed by garlic and mustard. The inhibitory effect increased with the addition of a greater quantity of spices. The optimal added concentration of spices for inhibition of total viable cell and proliferation of Escherichia coli in ground chicken meat was 2%, 4%, and 1.2% for rosemary, garlic, and mustard, respectively. The growth inhibition of total viable cells and E. coli differed during storage period for MixA (97.4%) > rosemary (96.9%) > MixB (96.3%) > garlic (53.7%) > mustard (33.3%). The addition of sterilized garlic to ground chicken meat showed that the total viable cells was low at 2.6-3.0 log CFU/g on the 0-day and 2.4-3.2 log CFU/g on the 9-day, and the number decreased as the storage lengthened. Non-sterilized garlic treatment showed a higher number of total viable cells than the control group, and this increased with elapse of storage time. The number of E. coli, was low at 0.4-1.0 log CFU/g on the 0-day and 0.5-1.5 log CFU/g on the 9-day for the sterilized group, and the change during the storage showed a similar trend for the total viable cells. In conclusion, the microbial safety of ground chicken meat products was improved by various mixed applications of rosemary, garlic, and mustard.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.649-654
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• 1989

The color distribution of fish sauces was studied by using the change in log absorbance per 100nm as a parameter of color tone. A linear relationship was found between the logarithm of absorbance (log A) and wavelength at 450 nm to 650 nm in the color of fish sauces. Change in log A per 100nm $({\Delta}A)$ in the color of the fish sauce products was in the range of 0.55 to 0.59. Absorbance at 450 nm (A 450) of the fish sauce treated with soy sauce koji was high in comparison with A 450 of the fish sauce treated by pronase and control. The color of fish sauces treated with soy sauce koji was dark reddish orange, and was similar to the color of soy sauce. A 450 of every fish sauce increased with the progress of fermentation but ${\Delta}A$of the fish sauces slightly increased at the beginning of fermentation and then decreased at the end of fermentation. In the results of sensory evaluation for the flavor of fish sauce products, the fish sauce product treated with soy sauce koji that 20% salt was added at the first stage was the molt desirable in the strength of flavor, tastefulness and after taste, and the fish sauce was also the best in acceptability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.464-477
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• 2013

There is a great need to develop a training program proven to change behavior and improve knowledge. The purpose of this study was to evaluate employee hygiene knowledge, hygiene practice, and cleanliness, before and after HACCP system implementation at one small-size restaurant. The efficiency of the system was analyzed using time-temperature control after implementation of u-HACCP$^{(R)}$. The employee hygiene knowledge and practices showed a significant improvement (p<0.05) after HACCP system implementation. In non-heating processes, such as seasoned lettuce, controlling the sanitation of the cooking facility and the chlorination of raw ingredients were identified as the significant CCP. Sanitizing was an important CCP because total bacteria were reduced 2~4 log CFU/g after implementation of HACCP. In bean sprouts, microbial levels decreased from 4.20 logCFU/g to 3.26 logCFU/g. There were significant correlations between hygiene knowledge, practice, and microbiological contamination. First, personnel hygiene had a significant correlation with 'total food hygiene knowledge' scores (p<0.05). Second, total food hygiene practice scores had a significant correlation (p<0.05) with improved microbiological qualities of lettuce salad. Third, concerning the assessment of microbiological quality after 1 month, there were significant (p<0.05) improvements in times of heating, and the washing and division process. On the other hand, after 2 months, microbiological was maintained, although only two categories (division process and kitchen floor) were improved. This study also investigated time-temperature control by using ubiquitous sensor networks (USN) consisting of an ubi reader (CCP thermometer), an ubi manager (tablet PC), and application software (HACCP monitoring system). The result of the temperature control before and after USN showed better thermal management (accuracy, efficiency, consistency of time control). Based on the results, strict time-temperature control could be an effective method to prevent foodborne illness.

• Preventive Nutrition and Food Science
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• v.12 no.3
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• pp.181-184
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• 2007

Effect of aqueous chlorine dioxide ($ClO_{2}$) treatment on quality change of mackerel during storage was examined. Mackerel treated with 0, 5, 10, and 50 ppm of $ClO_{2}$ solution, respectively was stored at $4^{\circ}C$. $ClO_{2}$ treatment decreased populations of aerobic bacteria in mackerel during storage. The number of total aerobic bacteria of mackerel treated with 50 ppm $ClO_{2}$ increased from 2.45 to 3.44 log CFU/g after 9 days of storage, while that of the control increased from 3.47 to 4.72 log CFU/g. The pH values of mackerel increased during storage, with no significant changes among treatments. Volatile basic nitrogen values of mackerel were decreased by $ClO_{2}$ treatment. Quality of mackerel treated with $ClO_{2}$ was better than that of the control during storage based on sensory evaluation. These results indicate that aqueous $ClO_{2}$ treatment could be useful for improving the microbial safety and qualities of mackerel.