• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.77-85
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• 1996

The study on the ripening of leather waste sludge was performed to vemistabilize the sludge effectively using a laboratory scale darkened wood box reactor ($10{\times}10{\times}20cm$). The acceptable feed conditions for earthworm of Eh, alkalinity were obtained in the 30th and 35th days, respectively. The value of pH was gradually decreased from 7.8 to 7.1 through the ripening time. The contents of heavy metals of the ripened sludge were estimated as lower levels compared to the other regulatory standards for compost. After the ripening time for 50days, the physico-chemical properties of the sludge were estimated as pH 7.1, water content 72%, redox potential 85mV, electrolytic conductivity $2,620{\mu}mhos/cm$ and alkalinity 450 ppm as $CaCO_3$, respectively. In the ripened sludge, survival rate of the earthworms for 50 days was about 75%, and the live weight increase rate was about 230% at the temperature range of $20{\sim}25^{\circ}C$. Moreover, hatching rate of the earthworm cocoons was about 87% and the highest value was obtained in the 20~30th days. From the above results, it was evaluated that leather waste sludge could be vermistabilized effectively by earthworms, when the sludge was ripened during 50 days.

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.145-149
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• 2015

The electrochemical behavior of $Nd_2O_3-La_2O_3-NiO$ mixed oxide including rare earth resources has been studied to synthesize $La_{0.5}Nd_{0.5}Ni_5$ alloy in a LiCl molten salt. The $Nd_2O_3-La_2O_3-NiO$ mixed oxide was converted to $NiNd_2O_4$ (spinel) and $LaNiO_3$ (perovskite) structures at a sintering temperature of $1100^{\circ}C$. The spinel and perovskite structures led a speed-up in the electrolytic reduction of the mixed oxide. Various reaction intermediates such as Ni, $NiLa_2O_4$ were observed during the electrochemical reduction by XRD analysis. A possible reaction route to $La_{0.5}Nd_{0.5}Ni_5$ in the LiCl molten salt was proposed based on the analysis result.

• Food Science and Preservation
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• v.18 no.4
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• pp.459-466
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• 2011

To investigate optimum temperature for storage of fresh ginseng (Panax ginseng C. A. Meyer), the quality of the ginseng was compared during its storage at $-3^{\circ}C$, $-1.5^{\circ}C$ and $0^{\circ}C$. The deterioration rate of fresh ginseng stored at $-3^{\circ}C$ was the lowest for 8 weeks after storage. The rate was rapidly increased after that time and the rate at $-3^{\circ}C$ was higher than that of fresh ginseng stored at $-1.5^{\circ}C$ or $0^{\circ}C$ after the 12th week of storage. The deterioration severity of the fresh ginseng stored at $0^{\circ}C$ was much higher than that of the ginseng stored at $-1.5^{\circ}C$ and $-3^{\circ}C$. The weight loss of fresh ginseng ranged from 0.7---- to 1.6---- after 16th week; it was the lowest in the ginseng stored at $-1.5^{\circ}C$ and similar in fresh ginseng stored at $0^{\circ}C$ and $-3^{\circ}C$. The number of viable cells and molds in the fresh ginseng stored at $-3^{\circ}C$ was smaller than the fresh ginseng that was stored at other temperatures for 12 weeks, but did not differ with different storage temperatures after the 14th week of storage. The surface color of the fresh ginseng at $0^{\circ}C$ or $-1.5^{\circ}C$ was changed little while the discoloration of fresh ginseng at $-3^{\circ}C$ was relatively great. The electrolytic leakage from the rhizome of the fresh ginseng stored at $-3^{\circ}C$ was higher than that of the rhizome stored at $-1.5^{\circ}C$ and $0^{\circ}C$. The overall sensory quality of the fresh ginseng dropped below 3.0 in the S-point scale after the 10th week of storage at $-3^{\circ}C$ and after the 14th week of storage at $-1.5^{\circ}C$ and $0^{\circ}C$ (p<0.05).