• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.05a
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• pp.97-97
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• 1999

Dross formation in the zinc bath is inevitable under any condition as long as coating process on steel strip continues. Thus, bath aluminum and temperature are precisely managed to suppress the increase of dross. Also, excessive dross for normal coating process is generally eliminated physically by bubbling and skimming. Total amount of dross in the bath can be sometimes high enough to cause coating defect. On the other hand, local concentration of dross can make coating defect even with satisfactory level of total amount of dross. Reduction of dross in the bath was attempted by using ceramic foam filter made of mainly alumina. Dross in molten zinc was almost reduced to the levels of solubility of iron and aluminum in molten zinc at $450~460^{\circ}C$. Their solubility levels were confirmed by thermodynamic calculations or DEAL program. Two kinds of filters were tested for dross reduction. One was #20 ppi, porous per inch, and the other #30 ppi filter. Both were effective in reducing the bath dross to the solubility levels at the static state. Bath iron was reduced by 24 wt% and 19 wt% with #20 filter, and by 35 wt% and 29 wt% with #30 filter for GI and GA pot, respectively. Also, ceramic foam filter did not make any harm to the zinc bath composition after filtering test.

• Journal of the Korean Society of Food Culture
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• v.30 no.6
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• pp.766-772
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• 2015

This research was conducted to investigate the effect of essential oil (EO) from Artemisia Princeps Pampanini on quality of tomato during storage. EO was extracted by steam distillation and diluted by 1 and 2%. Total phenolic contents and antioxidative activities of EO were analyzed. Tomato was packaged corrugated box covered with polypropylene (PP) film containing EO (1 and 2%) and then stored at room temperature for 10 days. During storage, appearance, weight loss rate, soluble solid contents, pH and a (redness) value were measured for tomato. Total phenolic contents of EO increased in a dose-dependence. The DPPH and ABTS radical scavenging activities also showed a concentration-dependent increase. The weight loss rate was lowest using the film packaged in 1% EO. During the storage period, soluble solid contents and pH increased in all treatments. The a value increased regardless of EO concentration in films. Especially, tomato packaged with EO film showed a lower a value than non EO-packaged ones. This result suggests that application of EO to film is effective for tomato quality preservation.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.111-116
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• 2004

The development of Aphis gossypii was studied at various constant temperatures ranging from 15 to 35$^{\circ}C$, with 60-70％ RH, and photoperiod of 16：8 (L：D h). Mortality of A. gossypii was high in the early developmental stages, and at high temperatures. The total immature developmental period ranged from 4.6 to 11.5 days. The lower developmental threshold temperature and effective cumulated temperature for all immature stages were 5.0$^{\circ}C$ and 106.8 degree-day, respective. The nonlinear shape of temperature-dependent development was well described by the modified Sharpe and DeMichele model. The normalized cumulative frequency distributions of developmental period for each life stage were fitted to the three-parameter Weibull function.

• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.35-41
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• 2016

Geothermal heat pump (GHP) systems have been proved to be one of the most efficient systems for heating and cooling in buildings. However, an optimal energy performance depends on a good control of the system components, including heat pumps and circulation pumps, which affect to the total energy consumption of system. This paper presents the simulation results of the heat pump performance for two different control schemes, i.e. constant setting temperature (Control-A) and variable setting temperatures (Control-B) in buffer tank. A dynamic simulation tool, TRNSYS 17, was used to model the entire system and to assess the performance of the system. Simulation results show that the Control-B, which controls the temperature in buffer tank with outdoor air temperature, is a effective way to reduce the energy consumptions in heat pump (7.7%) and circulation pump (7.5%).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.2
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• pp.70-77
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• 1999

This study was carried out to suggest an effective method for the rehabilitation of Close-to-Nature River and artificial wetland. The results on the revegetation methods by seeding and sodding of Phragmites japonica, Miscanthus sacchariflorus, Themeda triandra, and Pennisetum alopecuroides were summarized as follows. Seed germination of Phragmites japonica was 76.3% at $30^{\circ}C$, that of Miscanthus sacchariflorus was 68.7% at $20^{\circ}C$, that of Themeda triandra germinated 52.3% at $25^{\circ}C$, $30^{\circ}C$ constant temperature and that of Pennisetum alopecuroides germinated 86.7% at $30^{\circ}C/20^{\circ}C$ alternating temperature. Seed germination of Pennisetum alopecuroides exceeded 80% at $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$ constant temperature and $25^{\circ}C/15^{\circ}C$ alternating temperature. At 60 days after seeding, the ground coverage of Phragmites japonica, Miscanthus sacchariflorus, Themeda triandra, and Pennisetum alopecuroides reached 81%, 81 %, 74%, and 86% respectively in the soil media of vermiculite and peatmoss(1 : 1 by volume). In the results of sod experiment, Phragmites japonica, Miscanthus sacchariflorus, Themeda triandra, and Pennisetum alopecuroides were formed sod completely in soil composition type of vermiculite and peatmoss(1 : 1, v/v). Thus this media seems to be best sad production media for rehabilitation works of Close-to-Nature River and man-made wetlands. Phragmites japonica and Miscanthus sacchariflorus were not significantly different in shoot height and the number of tillers by different planting distance for the first one year of experiment. Pennisetum alopecuroides shows high possibility to be used for Close-to-Nature River rehabilitation works by seeding.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.665-675
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• 2007

In-situ Air Sparging (IAS, AS) is a remediation technique in which organic contaminants are volatilized from saturated zone to unsaturated layer. This study focuses on the removal and interaction of Volatile Organic Compounds (VOCs) and $CO_2$, and Total Petroleum Hydrocarbon (TPH) in saturated and unsaturated, and air space zone on the unsaturated soil surface. Soil sparging temperature of hot air has risen to $34.9{\pm}2.7^{\circ}C$ from $23.0{\pm}1.9^{\circ}C$ for 36 days. At the diffusing point, fluid TPH concentrations were reduced to 78.7% of the initial concentration in saturated zone when hot air was sparged. The TPH concentrations were decreased to 66.1% for room temperature air sparging. The amount of VOCs for hot air sparging system, in air space, was approximately 26% larger than constant air sparging system. The amount of $CO_2$ was 4,555 mg (in unsaturated zone) and 4,419 mg (in air space) when hot air was sparged was 3,015 mg (in unsaturated zone) and 3,634 mg (in air space) for room air temperature in the $CO_2$ amount. The removals of VOCs and biodegradable $CO_2$ through the hot air sparging system (modified SVE) were more effective than the room temperature air sparging. The regression equation were $Y=976.4e^{-0.015{\cdot}X}$, $R^2=0.98$ (hot air sparging) and $Y=1055e^{-0.028{\cdot}X}$, $R^2=0.90$ (room temperaure air sparging). Estimated remediation time was approximately 500 days, if final saturated soil TPH concentration was set to 1.2 mg/L application of tail effect.

• Journal of Environmental Science International
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• v.23 no.7
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• pp.1367-1373
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• 2014

This study was conducted to evaluate the effects of heating hatching eggs on the number of day-old chicks, egg temperature and egg weight during extended storage, and to provide basic information for improving hatchability to livestock producers. Eggs (Hy-line) were subjected to the following treatments: "control": eggs were maintained in an incubator after storage for 8 days; "T1": eggs were preheated for 8 hours at $23.9^{\circ}C$ after storage for 8 days in a hatchery; "T2": eggs were initially heated for 8 hours at $37.8^{\circ}C$ in an incubator and then preheated for 8 hours at $23.9^{\circ}C$ in a hatchery after storage for 8 days. The results were as follows: First, at the end of the experiment, the total number of day-old chicks was higher in T1, followed by T2 and then the control. This indicated that chick hatchability may be improved when eggs are preheated. Second, compared with the control, the number of day-old female chicks was expected to be higher in treatments with pre-heating; however, the results indicated the opposite effect. Third, as storage time lengthened, the factor that influenced preheating (the main effect and interactions) was not egg weight but egg temperature measured in the upper, middle and bottom parts of incubator. The temperatures recorded in all treatments ranged from 37.97 to $38.40^{\circ}C$ in the upper parts of incubator, 37.80 to $38.26^{\circ}C$ in the middle parts of incubator, and 37.94 to $38.59^{\circ}C$ in the bottom parts of incubator over storage. In conclusion, preheating was very effective in improving hatchability, and egg temperature was the main factor affecting preheating and hatchability.

• Journal of the Korean Society for Heat Treatment
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• v.5 no.4
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• pp.215-223
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• 1992

This study has been performed to investigate into some effects of temperature, gas mixing ratio and time on the optical microstructure, hardness and wear characteristics of medium carbon alloy steel treated by plasma nitriding. The results obtained from the experiment are summarized as follows: (1) Optical micrographs of AISI 4140 steel plasma-nitrided by the double stage technique have revealed that the nitrided layer is composed of the compound layer and the diffusion layer. The variation in temperature at the first stage gives effects, on the formation of compound layer and the growth rate is shown to be relatively fast at $460^{\circ}C$. (2) The thickness of compound layer has been found to increase with increasing nitrogen percentage in the gas mixture and the holding time. It is therefore recommended that a shorter holding time and a lower nitrogen percentage are more effective to produce a tougher compound layer and a diffusion layer only. (3) X-ray diffraction analysis for AISI 4140 steel has shown that the compound layer consist of ${\gamma}^{\prime}-Fe_4N$ and ${\alpha}-Fe$ and that tough compound layer diffustion layer only can be obtained by the double stage plasmanitriding process. (4) There is also a tendency that the total hardened layer depth increases with increasing temperature, time and nitrogen percentage in the first stage during the double stage plasma nitriding. (5) The wear resistance of plasma nitrided specimens has been found thobe considerably increased compared to the untreated specimens and the amount of increment has appeared to increase further with increasing nitriding temperature, holding time and notrogen percentage of gas mixture in the first stage treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.155-159
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• 2016

The objective of this study was to investigate the effect of fermentation temperature on quality characteristics of apple wine. Apple wine mashes were fermented in 15, 20, and $25^{\circ}C$ water bathes for 9 days. The pH levels of all samples were below 4 from 24 h of fermentation until the end. Total acidities of 0.05% acetic acid solution were 7.8, 7.4, and 7.0% in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. The evaporation of esters generated by combining alcohol and organic acids might be the reason for lower total acidity for high temperature fermentation. Alcohol contents of the 20 and $25^{\circ}C$ fermented samples were 6.5 and 6.6% (v/v), respectively, whereas that of the $15^{\circ}C$ fermented sample was 5.6% (v/v) and significantly lower than the others (P<0.05). Methanol contents were 0.68, 0.82, and 1.69 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. Fermentation at higher temperatures generated higher methanol content in apple wine. On the other hand, acetaldehyde contents were 3.43, 2.39, and 1.02 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively, due to the lower boiling point of acetaldehyde ($20.2^{\circ}C$). Based on the results, a fermentation temperature of $20{\sim}25^{\circ}C$ is effective for apple wine fermentation.