• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11b
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• pp.295-299
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• 2003

1. 고정화 $TiO_2$의 경우도 분말을 이용한 것과 같이 최적 광촉매 투입량이 나타났으며, 최적 투입량은 33.8 g/L이었고, 분말 $TiO_2$를 이용한 경우보다 빠른 초기반응속도를 보였으며, 최종반응시간도 빠른 것으로 나타났다. 2. 수용액에서 빠른 초기 제거속도의 1차적인 기작은 고정화 $TiO_2$ 표면으로의 흡착 때문이었으며, 빠른 흡착으로 인해 수용액 중의 RhB 농도가 빠르게 감소하여 광 투과율이 증가하므로 전체 반옹속도가 빠른 것으로 사료되었다. 3. 고정화 $TiO_2$를 이용한 유동층 반응기의 경우 최적 공기 공급량은 의한 Rhodamine B의 초기 제거속도는 분말보다 빠르지만 전체적인 제거시간은 흡착된 Rhodamine B의 분해 때문에 분말 $TiO_2$보다 느린 것으로 나타났다.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.23-28
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• 2011

The engine ground and altitude tests were carried out to investigate the effect of jet fuel alteration on the performance of a small turbojet engine. JP-S was supplied 8% higher than JP-8 by fuel metering system at the same command. The employment of JP-S showed the similar starting characteristic to that of JP-8, however, difference in the ignition time and acceleration rate of engine speed due to the difference of fuel flow rate by fuel metering system was observed. In spite of jet fuel alteration, the test results yield the similar steady-state engine performance in net thrust, air flow, exhaust gas temperature, etc. On the other hand, the fuel consumption of JP-S increased by 5 % compared with that of JP-8. In point of specific fuel consumption (SFC), SFC of JP-S was approximately 1.1~2.6 %, 5 % higher than that of JP-8 in ground and altitude tests respectively at the same thrust.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.432-437
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• 2010

A new device injecting secondary fuel behind flameholder was invented and tested in order to reduce low frequency combustion instability of combustor using V-gutter flameholder. Specially designed combustion device could make large combustion instability up to 180 dB successfully, and newly invented device made a success to reduce 110~120Hz low frequency pressure pulsation up to 84%. It was found that the fuel flow rate of secondary fuel supplying behind flameholder was the only parameter which dominates reduction of instability. It is considered that stabilized flame with sufficient secondary fuel can lead to break the connection between combustion system and acoustic system due to independence of flame from fluctuation of main fuel resulted from synchronization with acoustic wave.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.410-415
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• 2010

The engine ground and altitude tests were carried out to investigate the effect of jet fuel alteration on the performance of a small turbojet engine. JP-S was supplied 8% higher than JP-8 by fuel metering system at the same command. The employment of JP-S showed the similar starting characteristic to that of JP-8, however, difference in the ignition time and acceleration rate of engine speed due to the difference of fuel flow rate by fuel metering system was observed. In spite of jet fuel alteration, the test results yield the similar Steady-State engine performance in Net thrust, Air flow, Exhaust Gas Temperature, etc. On the other hand, the Fuel consumption of JP-S increased by 5 % compared with that of JP-8. In point of Specific Fuel Consumption (SFC), SFC of JP-S was approximately 1.1~2.6 %, 5 % higher than that of JP-8 in ground and altitude tests respectively at the same thrust.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.253-257
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• 2002

The time-dependent changes of red pigments production in solid-state plant scale fermentor using barley cultured with Monascus sp., instead of rice which was traditionally used, were investigated in this study. A steady increase in the yield of red pigments in barley occurred between the 3rd and 6th days. The optimized conditions (inoculation volume = 6∼8%, initial pH = 6, air supply = 0.6∼0.8 m) promoted the production of red pigments. Short-time steaming of barley (< 20 min) decreased fungal growth and pigments production due to the insufficient gelatiniza-tion. The optical density of the red pigments under the optimized conditions was 120 at 500 ]nm per gram of barley. In addition, the metabolites from the fermented barley with Monucus sp. showed antibacterial effects against Escherichia coli and Salmonella typhimurium. Barley was shown to be one of the best grain sources for solid-state fermentation with Monascu sp., fur obtaining natural pigments and also functional food materials.

• KSBB Journal
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• v.18 no.6
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• pp.529-535
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• 2003

We studied degradation effects of hydrophobic substrate such as kerosene and diesel by adding a biosurfactant originated from Pseudomonas aeruginosa F722 and chemical surfactants (Tween 80 and detergent) with aeration. The surface tensions of the biosurfactant, Tween 80 and detergent were 30mN/m, 39mN/m and 31mN/m, respectively. When the concentration of biosurfactant added in C-medium was 0.01 and 0.15%(w/v), the ratios of hydrocarbon degradation were 94.3％ and 94.2% respectively. It was 6.2%(w/v) higher than when the concentrations of added biosurfactant were 0.05, 0.1 and 0.2％. The degradation ratios of the chemical surfactants (Tween 80 and detergent) were 94.5％ and 93.5％ respectively. The effects of the biosurfactant and chemical surfactants were similar on the degradation ratio in mixtures of kerosene and diesel. However, the population of viable p. aeruginosa F722 at the end of the cultivation period was twice as higher in the biosurfactant than that in the chemical surfactant. We also studied the effect of aeration (0.5vvm) on the degradation ratio. The biosurfactant addition experiment was conducted with 0.5vvm air, 35$^{\circ}C$, 150rpm, pH 8.0, 3days, 1.0% (w/v) substrate. When p. aeruginosa F722 and 0.15%(w/v) biosurfactant were added, the degradation ratio of hydrocarbon was 94.8％. Without p. aeruginosa F722, it was 68%. Thus, with aeration, the degradation ratio of hydrocarbon was increased by 26.8％. In addition, the cultivation time was shortened by 1/3. The degradation ratios of hydrocarbon in shaking culture (cultivation time; 3days) and stationary culture (cultivation time; 10days) were 94.8 and 93.7％ respectively. Thus, the addition of biosurfactant and aeration enhanced the degradation of hydrocarbon originated kerosene and diesel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.955-961
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• 2009

Present, a portable battery have problem that the volume increases according to capacity Increase. Direct Methanol Fuel Cell is alternative by solution plan of this problem. In this paper, the characteristics of DMFC are analyzed by change in concentration and discharge of fuel in natural convection and room temperature condition. According to the analysis result, polarization by delay of diffusion velocity of hydrogen ion appeared in methanol of low concentration. And if have a lot of supplies of methanol, generation power declines by electric cell cooling effect.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.631-640
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• 2018

The application of an oxy-combustion circulating fluidized bed combustor (Oxy-CFBC) for low grade coals has recently developed in the world to meet the continuous increase of energy demand and to achieve the reduction of greenhouse gases. Since demo plants for Oxy-CFBC have been developed, the combustion properties of Oxy-CFBC in various operation conditions, such as gas flow rates, combustion temperature, fuel, and so on, should be investigated to develop design criteria for a commercial Oxy-CFBC. In this study, a computational simulation tool for Oxy-CFBC was developed on the basis of the IEA-CFBC (International Energy Agency Circulating Fluidized Bed Combustor) model. Simulation was performed under various conditions such as reaction temperature ($800^{\circ}C{\sim}900^{\circ}C$), oxygen contents (21%~41%), coal feeding rate, Ca/S mole ratio (1.5~4.0), and so on. Simulation results show that the combustion furnace temperature is higher in oxy 1 than air fired. However, the temperature gradient tended to decrease with increasing oxy mixing percent. In case of $SO_x$, the higher the Ca/S mole ratio and oxy mixing percent, the higher the desulfurization efficiency.

• Korean Journal of Medicinal Crop Science
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• v.12 no.6
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• pp.478-482
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• 2004

Suspension culture of Schisandra chinensis for production of gomisin J was perfomed in bioreactor. The inoculum size and initial sucrose concentration had significant effect on the cell growth and gomisin J accumulation. The maximum dry cell weight $(DCW;\;43.5\;g/{\ell})$ and gomisin J content $(0.71\;{\times}\;10^{-3}\;{\mu}g/g\;DCW)$ were obtained at inoculum size of 100 g fresh cell weight (FCW) per liter and MB5 medium containing 6% sucrose after 8 weeks of culture. The effect of oxygen supply on the cell growth and gomisin J accumulation was also investigated in an airlift-type bioreactor. The optimal cell growth and gomisin J content was obtained under 0.5 vvm. The productivity of gomisin J was 0.7 fold in bioreactor culture lower than that obtained in a flask cultivation.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.124-129
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• 2000

The purpose of this study is to estimate the degradation rate and process efficiency of the composting according to the salinity concentration. The samples of food waste for this study were collected in Pocheon-Gun, Kyungki-Do. The collected samples were adjusted to the optimum range of moisture content, pH and C/N ratio. After that, adding the saline, the samples with 3 different salinity concentrations(1%, 5% and 10%) were made. Then each sample was fed into the reactor with temperature controller. During the aerobic composting process, the change of the physical and chemical properties of the sample as temperature, pH, C/N ratio and $CO_2$ and $O_2$ concentration in the reactor were measured. From the experiment of this study, the result are following. The highest temperatures are $59^{\circ}C$ at RUN 1(1% salinity conc.), $49^{\circ}C$ at RUN 2(5% salinity conc.) and $45^{\circ}C$ at RUN 3(10% salinity conc.). The change of $CO_2$ production and $O_2$ consumption have the positive correlation with the change of the temperature. $CO_2$ production and $O_2$ consumption are peaked at the low salinity concentration. During composting, Run 1, RUN 2 and RUN 3 are increased pH to 8.9, 8.6 and 7.2 and slowly decreased C/N ratio to 18.9, 19.1 and 22.1 and moisture content to 51.1%, 53.7% and 55.0%, respectively. It is supposed that increasing salinity concentration causes the retarding of the microbial degradation activities during the composting. And for the efficient composting, the salinity concentration in the sample hat to be maintained below 5%.