• 한국전산유체공학회:학술대회논문집
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• 1998.11a
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• pp.204-210
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• 1998

A method is developed to include the effect of volume expansion in the description of the flame dynamics using G-equation. Line volume-source is used to represent the effect of the exothermic process of combustion with source strength determined by the density difference between the burned and the unburned region. Volume expansion adjusts the flow field to accommodate the increased volume flow rate crossing the flame front. Test result predicted the measured velocity field qualitatively. The method was applied to study the interaction of vortex and premixed flame. Increased volume expansion did not change the initial growth rate of flame area. However, the residence time and flame surface area increased with higher expansion ratios.

• Journal of Environmental Health Sciences
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• v.16 no.1
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• pp.21-28
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• 1990

As a research for treatment of waste water by biological method, we investigated general characteristics of waste water and isolated some useful bacteria which effectively treated waste water. Compositions of waste water were analyzed to give COD 2060 ppm, PVA 560 ppm, T-N 50 ppm, T-P 3.3 ppm and PH 12. Also, we inverstigated optimum nutrients requirement and growth conditions by mixed culture as well as the effect of coagulants. The COD removal rate reached maximum state for 48 hrs culture at pH 7.0 and 30$^{\circ}$C. Alum as the coagulated was the most effective. The COD removal rate was also increased by supplementing 10 ppm phosphorous sources as additional nutrients. The COD of waste water was reduced to 10% of its initial value by the continuous culture. As a result of overall experiments the COD of effluents became about 100 ppm and final pH 7.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.12
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• pp.1669-1680
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• 1998

A method is developed to include the effect of volume expansion in the description of the flame dynamics using G-equation. Line volume-source is used to represent the effect of the exothermic process of combustion with source strength assigned by the density difference between the burned and the unburned region. The present model provides good agreement with the experimental results. Including volume expansion, the flow field is adjusted to accommodate the increased volume flow rate which crossing the flame front and the result predicts the same behavior of measured velocity field qualitatively. The effect of increasing volume expansion does not change the initial growth rate of flame area but increase the residence time. Consequently this effect increases the maximum area of flame front. The flame propagation in varying flow field due to volume expansion provides a promising way to represent the wrinkled turbulent premixed flames in a numerically efficient manner.

• Mycobiology
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• v.40 no.3
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• pp.168-172
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• 2012

In this study, the effect of soil ameliorators on ectomycorrhizal (ECM) fungal communities in coal mine spoils was investigated. Organic fertilizers and slaked lime were applied as soil ameliorators in 3 abandoned coal mine spoils. One year after the initial treatment, roots of Pinus densiflora seedlings were collected and the number of ECM species, colonization rate, and species diversity were assessed. The results showed that the soil ameliorators significantly increased ECM colonization on the roots of P. densiflora. The results suggest that soil ameliorators can have a positive effect on ECM fungi in terms of growth of host plants and show the potential use of soil ameliorator treatment for revegetation with ECM-colonized pine seedlings in the coal mine spoils.

• Journal of Korean Society on Water Environment
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• v.33 no.1
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• pp.8-14
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• 2017

Microcystis aeruginosa (M. aeruginosa) is a cyanobacterium species that can form harmful algal blooms in freshwater bodies worldwide. The use of pine needle extract (PNE) to control nuisance algae by allelopathic inhibition will be environmentally friendly and promising. PNE removed successfully upto 98% of M. aeruginosa at the following optimal conditions: pH 7, $25^{\circ}C$ of temperature, 100 rpm of mixing rate, 5 min of mixing time. These results was indicated that the amount of 1 g/L PNE was removed 1g dryweight/L of M. aeruginosa. The kinetic data showed substrate inhibition kinetics and maximum growth rate was obtained when the M. aeruginosa was grown in medium containing 0.5 g/L of initial concentration of PNE. Different substrate inhibition models were fitted to the kinetic data and found the Luong model was best. The model predicted kinetic parameters were in agreement with the experimental findings. The natural extract, PNE, can be a promising inhibition due to its high efficiency and low dose requirements.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.107-108
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• 2013

In this study, combustibles investigation and fire growth rate experiment were performed for predicting initial fire behavior in buildings. Combustibles investigation was performed for residential buildings, which is most frequently affected by fire in Korea. Spatial characteristics and combustibles properties were separately investigated, and occupied area and layout characteristics of combustibles were identified to produce general layout models. Of the layout models, room was selected for fire test of a single compartment. From this test, fire propagation for each combustible was identified, which was delayed compared to the summed heat release rate of a single combustible.

• Journal of Life Science
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• v.19 no.4
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• pp.457-461
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• 2009

We optimized dextranase culture conditions by batch fermentation using Lipomyces starkeyi KCTC 17343. Furthermore, dextranase was purified by an ultra-membrane, and then dextran hydrolyzates were characterized. Cell growth and dextranase production varied depending on the initial culture pH and temperature. The conditions of optimal dextranase production were met in a pH range of 4-5 and temperature between $25-30^{\circ}C$. At optimal fermentation conditions, total enzyme activity and specific enzyme activity were about 4.85 IU/ml and 0.79 IU/g cells, respectively. The specific growth rate was examined to be $0.076\;hr^{-1}$. The production of dextranase in culture broth was very stably maintained after mid-log phase of growth. The enzyme hydrolyzed dextran into DP (degree of polymerization) 2 to 8 oligodextran series. Analysis of the composition of hydrolysates suggested that the enzyme produced is an endo-dextranase.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.2
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• pp.157-162
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• 2018

A feeding trial was conducted to investigate the effects of supplementation with four phosphorus (P) additives [mono-calcium phosphate (MCP), dicalcium phosphate (DCP), tricalcium phosphate (TCP) and magnesium hydrogen phosphate (MHP)] on the growth, feed utilization and whole body mineral composition of juvenile olive flounders Paralichthys olivaceus. A basal diet without P supplementation was prepared as a negative control and four supplemental P sources were added at a level of 2%. Triplicate groups of fish (initial mean body weight 11 g) were fed one of the experimental diets to apparent satiation twice a day, at 08:30 and 18:00 for 10 weeks. The final body weights of fish fed the experimental diets ranged from 29.4 g (DCP) to 34.2 g (MCP) and did not differ significantly (P>0.05) among treatments. Similar tendencies were found for all parameters including weight gain (%), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), feed intake (FI) and survival rate (SR). The hematocrit (%), hemoglobin (g/dL), serum inorganic P and whole body mineral composition did not differ significantly different (P>0.05) among the treatments. Therefore, dietary P addition is not necessary for juvenile olive flounder fed a fish meal-based diet.

• Journal of Food and Nutrition Research
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• v.9 no.7
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• pp.363-366
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• 2021

This study aimed to determine the effect of regulating crude protein (CP) levels in total mixed ration (TMR) on the growth performance and carcass characteristics of Hanwoo steers. The regimens were divided into a control group (TMR with 15% CP) and treatment group (TMR with 12.5% CP). The viable cell count and fermentation potential of the prepared experimental feed and the nutrient digestibility were evaluated. Growth performance and carcass characteristics were confirmed by evaluating the weight and intake of Hanwoo steers, and an economic analysis was performed. Only CP digestibility was higher in the control group than in the treatment group (p<0.05). There were no significant differences in the initial and final body weights, daily gain, and feed requirements between the groups (p>0.05). There were no significant differences in carcass weight, yield index, back fat thickness, and loin area (p>0.05), but the appearance rate of quality grade A was higher in the treatment group than in the control group. In addition, there was no difference in the meat quality characteristics, such as marbling, meat color, fat color, texture, and maturity (p>0.05), and the treatment group had a higher rate of 1++ grade than the control group. Economic analysis showed that when 10 cattle were shipped, the control group received a price of 100,041 thousand won, and the treatment group received a price of 102,033 thousand won. When the income for each group was calculated, the production cost of the treatment group was 8% lower than that of the control group; thus, a higher net profit could be expected considering the low feed cost. Therefore, the economic feasibility of steer raising could be improved while maintaining productivity by controlling CP levels in feed. In addition, this study provides useful basic data for precisely adjusting the CP levels in feed for Hanwoo steers.

• Journal of Aquaculture
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• v.22 no.1
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• pp.1-4
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• 2009

A 10-week feeding trial was conducted to investigate the effects of feeding rate on growth and body composition of adult flounder during the summer season. Three replicated groups of the fish (initial mean weight of $535{\pm}4.1\;g$) were hand-fed a extruded diet twice a day at the different feeding rates of satiation (100%), 90%, 80% and 70% of satiation for 10 weeks. Mean Water temperature was $19.2{\pm}2.8^{\circ}C$ during the feeding trial. Weight gain and condition factor increased significantly with increase in daily feeding rate (P<0.05), but there was no significant difference in weight gain of fish fed the diet between 100% and 90% of satiation. Survival and feed efficiency were not significantly different among all groups. Proximate composition of dorsal muscle was not significantly affected by feeding rate. Based on the results of this study, optimum feeding rate for growth and condition factor of adult flounder (535-928 g) seemed to be 90% of satiation.