• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.494-501
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• 2010

The purpose of this study was to examine the presence of Bacillus cereus, aerobic bacteria and coliforms in the raw material of infant formulas and investigate the manufacturing process in terms of microbial safety. Among ten kinds of raw infant formula material samples (n=20), Bacillus cereus appeared in two (n=4). Aerobic bacteria were not detected in raw infant formula material or maximum 4.15 log CFU/g. Eleven species of aerobic bacteria were isolated and 76% of them were Sphingomonas paucimobilis, Pseudomonas fluorescens, Rhizobium radiobactor, or Stenotrophomonas maltophilia. A Pearson's correlation analysis revealed that the most influential factors for detecting Bacillus cereus were aerobic bacteria and coliforms. In other words, when the measured values of aerobic bacteria and coliforms were higher, the possibility that Bacillus cereus would appear increased. In a regression model to predict Bacillus cereus, the rate of appearance was correlated with aerobic bacteria and coliforms, and its contribution rate for effectiveness was 86%. Improving microbial quality control by pasteurization, spray dry, popping and extrusion resulted in a decrease in the numbers of Bacillus cereus, aerobic bacteria and coliforms in the raw materials. The results suggest that a hazard analysis and critical control point system might be effective for reducing microbiological contamination.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.307-318
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• 2010

This study was to analyze the ecological conditions, based on physical habitat, chemical, and biological conditions before (2006, 2007) and after ecological restoration (2009) in five sites of Changwon Stream (CS) and six sites of Nam Stream (NS), respectively, and then to compare ecological health between the two period. The analysis of ecological health was based on the multimetric models of Index of Biological Integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) along with water chemistry in the streams. For the study, the models of IBI and QHEI were modified as 8 and 11 metric attributes, respectively. For the evaluations, the survey was conducted in the period of 2006~2007 before the restoration and in 2009 after the restoration by the city. Chemical conditions, based on conductivity, in both streams showed a typical longitudinal declines along the axis of the upstream-to-downstream. There were no significant differences (p>0.05) in water quality between the two periods. Values of IBI in the CS and NS averaged 21.6 and 19.7, respectively, indicating a C grade in the criteria of Ministry of Environment, Korea, and there was no significant differences in the IBI between the two periods. Values of QHEI after the restoration averaged 29.2 and 63.2 in the CS and NS, respectively and the values decreased markedly especially, in the NS (35.3) after the restoration. The habitat disturbance was mainly attributed to destructions (i.e., the narrower width of riparian vegetation and higher substrate exposure by the air) of artificial materials by massive flood in 2009. Overall, our results suggest that the restoration was not effective in the two streams between the two periods, even if the budget was used a lot and that such ecological restoration, not considered the natural disaster, may not effect for the stream restoration.

• Korean Journal of Food Science and Technology
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• v.11 no.1
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• pp.1-7
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• 1979

This experiment was carried out to investigate the nutritive value of brewery's activated sludge on the performance and nutrients utilization of egg type chicken of babcock fed the different levels of sludge. The chemical composition, content of amino acids and mineral in brewery's activated sludge were also analyzed. 3,6,9 and 12% of brewery's activated sludge were supplemented with basal ration as a substituted ingredient to soybean oil meal in experimental ration. The results obtained were as follow: 1. Chemical composition analysis 1) Brewery's activated sludge had 42.50% of crude protein on the air dried basis, and had 15,69% of crude ash, and had 2,060 kcal of metabolizable energy per kg of sludge. 2) Total amino acid content of brewery's activated sludge was 42.50% and 99% crude protein of brewery's activated sludge was a true amino acid, and brewery's activated sludge contained especially more methionine and threonine that those of soybean oil meal. 3) In case of mineral content of brewery's activated sludge, phosphorus, magnesium, copper and iron were plentifully included. However, calcium content in brewery's activated sludge was very low. 2. Feeding trial 1) Body gain of chicken fed the different levels of sludge was decreased in proportion to increasing level of sludge was decreased in proportion to increasing level of sludge. However, no statistical differences were found out between treatments. 2) Diet intake of chicken fed the different levels of sludge was significantly (p<0.05) increased as the supplementation level of sludge in ration increased. 3) Feed conversion of chicken fed the different levels of sludge was high in proportion to increasing level of sludge in ration. However, there were no significant differences between treatments. 3. Digestion trial 1) Utilization of dry matter of chicken fed the different levels of sludge was decreased as the level of sludge in ration increased. However, no statistical differences were found out between treatments. 2) Utilization of crude protein of chicken fed the different levels of sludge was significantly (p<0.01) increased as the level of sludge was higher. Utilization of crude protein of control treatment and of sludge 3% treatment was higher than that of other treatments. 3) Utilization of crude ash of chicken fed the different levels of sludge was significantly (p<0.05) decreased in proportion to increasing level of sludge in ration. 4) Utilization of NFE of chicken fed the different levels of sludge was slightly decreased in proportion to increasing level of sludge in ration. However, no statistical differences were found out between treatments. Therefore according to this experiment, it may be concluded that brewery's activated sludge can be supplemented with chicken ration by $6{\sim}9%$.

• Membrane Journal
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• v.21 no.1
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• pp.22-29
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• 2011

During the maintenance, repair and replacement process of circuit breaker, $SF_6$ reacted with input air in arc discharge, which led to the production of by-product gases (eg, $N_2$, $O_2$, $CF_4$, $SO_2$, $H_2O$, HF, $SOF_2$, $CuF_2$, $WO_3$). Among these various by-product gases, $N_2$, $O_2$, $CF_4$ is major component. Therefore, the effective separation process is necessary to recycle the $SF_6$ gas from the mixture gas containing $N_2$, $O_2$, $CF_4$. In this study, the membrane separation process was applied to recycle the $SF_6$ gas from the mixture gas containing $N_2$, $O_2$, $CF_4$. The concentration of $SF_6$ gas in gas produced from the electric power industry is over than 90 vol%. Therefore, we made the simulated gas containing $N_2$, $O_2$, $CF_4$, $SF_6$ which the concentration of $SF_6$ gas is minimum 90 vol%. From the results of membrane separation process of $SF_6$ gas from $N_2$, $O_2$, $CF_4$ $SF_6$ mixture gases, PSF membrane shown the highest recovery efficiency 92.7%, in $25^{\circ}C$ and 150 cc/min of retentate flow rate. On the other hand, PC membrane shown the highest recovery efficiency 74.8%, in $45^{\circ}C$ and 150 cc/min of retentate flow rate. Also, the highest rejection rate of $N_2$, $O_2$, $CF_4$ is 80, 74 and 58.9% seperately in the same operation condition of highest recovery efficiency. From the results, we supposed the membrane separation process as the effective $SF_6$ separation and recycle process from the mixture gas containing $N_2$, $O_2$, $CF_4$, $SF_6$.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.635-649
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• 2007

Geochemical composition, stable isotopes $({\delta}^{18}O,\;{\delta}D,\;{\delta}^{34}S)$ and noble gases(He, Ne and Ar) of nine hot spring water and three groundwater for five hot springs(Jukam, Hwasun, Dokog, Jirisan, Beunsan) from the Honam area were analyzed to investigate the hydrogeochemical characteristics and the hydrogeochemical evolution of the hot spring waters, and to interpret the source of sulfur, helium and argon dissolved in the hot spring waters. The hot spring waters show low water temperature ranging from 23.0 to $30.5^{\circ}C$ and alkaline characteristics of pH 7.67 to 9.98. Electrical conductivity of hot spring waters is $153{\sim}746{\mu}S/cm$. Groundwaters in this area were characterized by the acidic to neutral pH range$(5.85{\sim}7.21)$, the wide electrical conductivity range $(44{\sim}165{\mu}S/cm)$. The geochemical compositions of hot spring and groundwaters can be divided into three water types: (1) $Na-HCO_3$ water type, (2) Na-Cl water type and (3) $Ca-HCO_3$ water type. The hot spring water of $Ca-HCO_3$ water type in early stage have been evolved through $Ca(Na)-HCO_3$ water type into $Na-HCO_3$ type in final stage. In particular, Jurim alkaline(pH 9.98) hot spring water plotted at the end point of $Na-HCO_3$ type in the Piper diagram is likely to arrive into the final stage in geochemical evolution process. Hydrogen and oxygen isotopic data of the hot spring water samples indicate that the hot spring waters originated from the local meteoric water showing latitude and altitude effects. The ${\delta}^{34}S$ value for sulfate of the hot spring waters varies widely from 0.5 to $25.9%o$. The sulfur source of most hot spring waters in this area is igneous origin. However, The ${\delta}^{34}S$ also indicates the sulfur of JR1 hot water is originated from marine sulfur which might be derived ken ancient seawater sulfates. The $^3He/^4He\;and\;^4He/^{20}Ne$ ratios of the hot spring waters range from $0.0143{\times}10^{-6}\;to\;0.407{\times}10^{-6}\;and\;6.49{\sim}584{\times}10^{-6}$, respectively. The hot spring waters are plotted on the mixing line between air and crustal components. It means that the He gas in the hot spring waters was mainly originated from crustal sources. However, the JR1 hot spring water show a little mixing ratio of the helium gas of mantle source. The $^{40}Ar/^{36}Ar$ ratios of hot spring water are in the range from $292.3{\times}10^{-6}\;to\;304.1{\times}10^{-6}$, implying the atmospheric argon source.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.1
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• pp.17-23
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• 1976

In order to investigate the fate of nitrogen in the paddy soil, Suchang, Hwasoon and Susan soil which have different properties, were treated with several nitrogen fertilizers such as ammonium chloride, ammonium sulfate, urea and SCU (sulfur-coated urea), and incubated under water-logged condition in $30^{\circ}C$ incubator. $NH_4-N$, $NO_3-N$, $Fe^{++}$ and pH in soil and stagnant water, were determined at 10, 20, 30, 40 and 50 days after incubation. The obtained results were summarized as follows: 1. The effect of rising temperature was increased in order of Hwasoon>Suchang>Susan and the effect of air drying soil was risen in order of Susan>Hwasoon>Suchang, while the rate of ammonication was in order of Susan>Suchang>Hwasoon. 2. The changes of $NH_4-N$ in stagnant water was dependent upon the nitrogen concentration of $NH_4Cl$ and $(NH_4)SO_4$ plat was high and decreased after 30 days incubation, but increased after 40 days and then decreased again. In contrast with the above, $NH_4-N$ concentration of urea and SCU plot was low but the change showed slightly through the incubation period. 3. Accumulation of $NH_4-N$ in the oxidative layer of the $NH_4Cl$ and $(NH_4)_2SO_4$ plot was higher than that of urea and SCU plot and $NH_4-N$ content was decreased with the incubation period. The change of $NH_4-N$ in the reductive layer showed the same pattern. 4. The changes of $NO_3-N$ in the stagnant water were different according to soil properties and nitrogen fertilizer. $NO_3-N$ concentration in stagnant water of urea and SCU plot was higher than in the $NH_4-Cl$ $(NH_4)_2SO_4$ plot and nearly disappeared after 30 to 40 days incubation. 5. The $NO_3-N$ concentration in the oxidative layer of soil was higher than reductive layer. The pattern of change was different in accordance with soil properties and nitrogen fertilizers. In general, nitrification in urea and SCU plot was more increased than $(NH_4)_2SO_4$ plot. In reductive layer, the concentration of $NO_3-N$ was very low until 30 days incubation and thereafter increased slightly. 6. Upon the concentration of $NH_4-N$ and $NO_3-N$ in stagnant water and soil, it was assumed that denitification of urea and SCU plot was higher than $NH_4Cl$ and $(NH_4)_2SO_4$ plot and denitrified nitrogen in incubation period was above 50%.