• Journal of Korean Society of Water and Wastewater
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• v.34 no.1
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• pp.61-73
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• 2020

Tetracycline is one of the most commonly used antibiotics in domestic and foreign livestock industries to suppress the growth of pathogens. Tetracycline has been reported as a non-biodegradable compound. Therefore it has been not completely removed in the sewage treatment process. In this study, tetracycline was degraded using liquid ferrate (VI). Based on these experiments, the optimal water condition (pH and water temperature) were selected, appropriate liquid ferrate (VI) dosage was calculated, and finally the degradation pathway was estimated with the intermediate products detected by LC/MS/MS. All degradation experiments were completed within 30 seconds and the optimal condition was obtained in basic condition (pH 10) at room temperature (20℃). And the appropriate molar ratio between tetracycline and liquid ferrate (VI) was 12.5:1. Finally, 12 intermediate products were detected with LC/MS/MS and the degradation pathways and the degradation pathways and proposed the degradation pathways.

• Journal of the Korean Society of Clothing and Textiles
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• v.46 no.3
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• pp.390-406
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• 2022

This study aims to establish the optimal environmental conditions for storing textile products. Four textile products (cotton, wool, nylon, cotton/polyurethane) were used to produce experimental fabrics according to artificial contamination and washing conditions. Each fabric was subjected to three environmental conditions (A: 20-25℃/20% RH, B: 20-25℃/50% RH, C: 30-35℃/65% RH) for 4-12 weeks. Changes in textile characteristics include tensile strength, wrinkle recovery rate, and odor intensity. Results show that the change in tensile strength for the four test fabrics slightly decreased with a storage time of 4 to 12 weeks. The wrinkle recovery rate of the fabrics was the lowest under the C condition. UV exposure causes a substantial decrease in the tensile strength of the textiles. The change in odor characteristics was the highest for the odor intensity in the C condition. For storing textile products for sustainable management, it is desirable to maintain a temperature of 20 to 25℃ with a relative humidity of 50% RH or less and to provide ventilation in an enclosed storage space that can also block UV rays.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.53-58
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• 2017

The rebound hammer test and the measurement of ultrasonic pulse velocity(UPV) have been widely used for the physical properties & condition evaluation of reinforced & prestressed concrete structures for a long time, but the acoustoelastic effects by the prestressing in the prestressed concrete structures on the rebound number and ultrasonic pulse velocity have not been studied clearly. Therefore, this study investigated the data distribution of the rebound numbers and ultrasonic pulse velocities in reinforced and prestressed concrete slabs of $3000{\times}3000mm$ with a thickness of 250 mm. Also, the Kolmogorov-Smirnov goodness-of-fit test was done in order to identify statistical consistency and reliability. The statistical analysis results show that the rebound number and ultrasonic pulse velocities increased about 1.9% and 2.5%, respectively when prestressing was applied. As expected, the UPV shows better statistical reliability and potential for in situ evaluation than the RB because the RB are more sensitive to testing posture, surface condition, temperature and humidity so on. The experimental data in this study can be used for the condition assessment of reinforced and prestressed concrete structures by the rebound number and ultrasonic pulse velocity.

• Journal of Environmental Health Sciences
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• v.12 no.1
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• pp.1-14
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• 1986

This investigation was carried out on the study of Ferrite formation by aerial oxidation of Fe $(OH)_2$ suspension of aqueous solution containing heavy metal ions. In this study the optimum reactionary condition of the Ferrite formation in Batch reactor wa studied by aerial oxidation which are subjected to various reaction time and temperature, under the different kinds of R(2NaOH/$FeSO_4$) Values, pH, Air flow rate, and $Fe^2+/M^2+$ mole ratio. The optimum condition for the Ferrite formation in Batch reactor was such that residence Time was 90 min., Temperature $65{\circ}$C, pH 11.0, Air flow rate 2.0l/min and $Fe^{2+}/M^{2+}$ mole ratio 4.0, which was observed by X-Ray diffraction analysis. The relation R-value, pH and ORP affecting the formation of Ferrite is that the jump step in pH 11.0, when a amount of NaOH is added, is steady state to the formation of Ferrite. Effect of R-value of $FeSO_4$ and $FeCl_2$ on the formation of Ferrite in different from each other the optimum condition of the in different from each other the optimum condition of the $FeCl_2$ is R-value 0.7, pH 11.0 and the $FeSO_4$ R-value 1.2, pH 11.0.

• The Korean Nurse
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• v.21 no.4 s.117
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• pp.65-79
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• 1982

Some report presented to nowadays college students were likely to have psychiatric problem mort and more because their many .other- environmental condition and they were greatly obstructed in mental health condition. Therefore this study was attempted com

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.174-176
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• 2003

A survey was conducted to investigate the sanitary condition of school kitchens in one region of Korea. A self-administered questionnaire recommended by the Korea Ministry of Education & Human Resources Development (MOEHRD) was offered to a random sample of dieticians of twenty-five elementary schools for food, sanitation and safety inspection of their kitchens. Air temperature, relative humidity, and airborne microbes in the kitchens were monitored during food preparation, processing and service. The inspection results showed their sanitary condition met the level B of the recommendation of the Korea MOEHRD. The range of air temperature of the kitchens was 21.4∼22.4$^{\circ}C$, and the range of relative humidity was 62.4∼69.6%. The microbiological evaluation of kitchen samples indicated aerobic plate count levels from 22.5 to 26.5 CFU/15 min. These results indicate that the levels of sanitary condition of kitchens in the schools were not satisfactory for safe foodservice although the inspection showed good results. This study suggests that the school kitchens should be monitored and strict inspection is necessary.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.327-332
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• 2002

Optical microscope, SEM (Scanning Electron Microscopy) and fluorescent microscope were used for qualitative and morphological studies of the attached biomass on PE (polyethylene) substratum under anaerobic condition. It was shown by the observation of optical microscope that the initial attachment of biomass began in crevices of the surface of PE. The shape and structure of the attached biofilm could be observed by SEM photographs, but species of bacteria were and methanogens were not classified. A large number of methanogenic bacteria were identified on the surface of PE substratum by fluorescence under 480nm of radiation. It was estimated that methanogenic bacteria was also related to initial attachment of biomass under anaerobic condition.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1103-1108
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• 2002

In order to evaluate the degradation organophosphorus pesticide, EPN, in water environment, the effects of water temp.(10$^{circ}C,\;30^{\circ}C$), pH(3-11) and sunlight on its degradation were investigated during 10 days. The degradation rate of EPN(200 rpm) was faster at higher water temp. and higher pH, i.e., its degradation rate at pH 3, 5, 7, 9, 11 was 57, 63, 66, 69, 75%(1$0^{\circ}C$), and 70, 74, 79, 91, 97%(3$0^{\circ}C$) after 10 days, respectively. The effect of water temp. on its degradation was little in acidic condition, but was rather great in alkaline condition, with time. EPN was degraded fast at the alkaline condition by photolysis. At the condition of pH 11, EPN was degraded fast at the early stage in the first 2 days, but after that the degradation rate was weakened.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.601-608
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• 2003

Thermal analyses have been carried out for a spent fuel dry storage cask under normal and off-normal conditions. Environmental temperature is assumed to be $15^{\circ}C$ under the normal condition. The off-normal condition has an environmental temperature of $38^{\circ}C$. An additional off-normal condition is considered as a partial blockage of the air inlet ducts. Two of the four air inlet ducts are assumed to be completely blocked. The maximum temperatures of the fuel rod and concrete overpack were lower than the allowable values under the normal condition. Temperature distributions for the off-normal conditions were slightly higher than the normal conditions.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.75-85
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• 2013

This study investigated the effects of organic matter decomposition on the emission of greenhouse gas under the influence of environmental factors such as change of climate condition ($CO_2$ concentration and temperature), vegetation, and N concentration in the soil of Gyeongan stream in the laboratory. The experimental results showed that organic matter decomposition and $CH_4$, $CO_2$ flux were influenced by changes of complex environmental conditions. Organic matter decomposition rate was affected by changes of climate condition with N concentration and climate condition with vegetation. Through the results of $CH_4$, $CO_2$ flux, $CH_4$ flux was affected by change of climate condition with N concentration and climate condition with vegetation and affected by the presence of vegetation and N concentration. $CO_2$ flux was affected by change of climate condition with vegetation and vegetation with N concentration. According to results of the study, change of (1) climate conditions, (2) vegetation, and (3) N concentration, each have an effect on organic decomposition rate, that also influences emission of greenhouse gas. It is known that climate change is related to an increase in greenhouse gasses in the atmosphere However, additional study will be needed whether vegetation could remove positive effect of nitrogen addition in soil since this study shows opposite results of organic matter decomposition in response to the nitrogen addition.