• 한국수소및신에너지학회논문집
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• 제17권4호
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• pp.379-388
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and conducted for hydrogen production under the anaerobic fermentation of sucrose. Each bioreactor consisted of the column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed by the different hydraulic retention time(HRT), and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% of biogas throughout the operation. Hydrogen production rate was increased till $10.5\;L{\cdot}h^{-1}{\cdot}L^{-1}$ of bioreactor when influent sucrose concentrations and recycle rates were varied. At the same time, the hydrogen production rate with hydrophobic media application was higher than its hydrophilic media application. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate, butyrate and lactate. In order to run in the long term operation of both reactor filled with hydrophilic and hydrophobic media, biofilm accumulation on hydrophilic media and biogas produced should be controlled through some process such as periodical backwashing or gas-purging. Four sample were collected from each reactor on the opposite hydrogen production rate, and their bacterial communities were compared by terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR products generated using bacterial 16s rRNA gene primers (8f and 926r). It was expressed a marked difference in bacterial communities of both reactors. The trickling bed bioreactor with hydrophobic media demonstrates the feasibility of the process to produce hydrogen gas. A likely application of this reactor technology can be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

• KSBB Journal
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• 제20권6호
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• pp.425-430
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• 2005

1. $H_2$ 생산속도와 $H_2$ 수율의 안정화를 근거로 판단컨대 start-up 기간은 30일 이내로 나타나 중온 CSTR에 비해 짧은 편이었다. 2. 고온 CSTR의 최고 $H_2$ 수율은 2.4 mol $H_2/mol$ glucose로 나타나 보고 된 중온의 것에 비해 우수한 편에 속하였다. 3. 운전 초기에 $CH_4$이 발생하였으나 14일 이후부터는 pH를 5.0 이하로 유지하면 거의 검출되지 않는 것으로 봐서 메탄생성균이 식종균에 남아 있더라도 반응기 운전 조건을 통해 $CH_4$ 발생을 억제할 수 있었다. 4. 고온 CSTR은 초기 운전 후에 적용한 운전조건의 변화(유입 포도당 농도, pH, 및 온도)에 민감한 것으로 나타났다. 특히 pH 및 온도변화에 대해 $H_2$ 생산속도와 $H_2$ 수율, 포도당 제거율 면에서 반응기 성능의 감소 및 불안정이 나타나, 운전 조건 변화 후에 나타난 고온 CSTR의 성능회복이 쉽지 않음을 알 수 있었다. 5. 문헌에 보고 된 중온 CSTR과는 달리 고온 CSTR는 일정한 조건에서도 불안정 한 성능을 나타내기도 하였다. 6. 불안정한 반응기 성능은 lactate 농도 증가와 더불어 n-butyrate와 acetate 농도 감소를 동반하였다. 생산된 n-butyrate와 acetate의 농도는 lactate의 농도변화와 반대의 경향을 나타내었다. 7. 비교적 긴 HRT와 침전조를 이용한 biomass의 재순환에도 불구하고, 유입 포도당의 농도가 낮아 biomass 농도는 다른 중온 반응기에서 보고된 것에 비해 낮은 편이었다. 8. T. thermosaccharolyticum와 계통발생학적으로 관련된 개체군이 반응기 운전 후 약 40일부터 우점으로 나타나 반응기 성능과 상관없이 그 이후로 계속 우세한 것으로 나타났다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.289-294
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• 2002

Cellulose production by Acetobacter pasteurianus was investigated in static culture using four bioreactors with silicone rubber membrane submerged in the medium. The shape of the membrane was flat sheet, flat sack, tube and cylindrical balloon. Production rate of cellulose as well as its yield on consumed glucose by the bacteria grown on the flat type membranes was approximately ten-fold greater than those on the non-flat ones in spite of the same membrane thickness. The membrane reactor using flat sacks of silicone rubber membrane as support of bacterial pellicle can supply greater ratio of surface to volume than a conventional liquid surface culture and is promising for industrial production of bacterial cellulose in large scale.

• Nuclear Engineering and Technology
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• 제38권1호
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• pp.33-44
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• 2006

This paper presents a review of small-to-medium-sized, pressurized-water-cooled nuclear power reactors whose major primary coolant systems are integrated into a reactor pressure vessel, the concepts categorized as Integrated Primary System Nuclear Reactors (IPSRs). Typical examples of these proposals of interest in this review are CAREM, SMART, IRIS and IMR, all of which are being aimed at the near term deployment. Emphasis is placed on thermal hydraulic aspects. A brief characterization of the IPSR concepts is made and comparisons of plant key parameters are shown. Discussions will follow for the core cooling under rated power conditions and natural circulation heat removal on the basis of the design data available in the public domain.

• 펄프종이기술
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• 제35권5호
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• pp.80-86
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• 2003

The wood-degrading fungus Trichophyton sp. LKY-7 (T. LKY-7) was immobilized in ca-alginate beads for laccase production and PCP bioremediation. The immobilized T. LKY-7 enabled the repeated use of this fungus for laccase production and produced high amount of laccase throughout 5 cycles incubation. As a laccase inducer. oak wood meal (Quercus variabilis) seemed to be effective laccase inducer for T. LKY-7, and the optimum addition amount was 1％ (W/W) in glucose-peptone medium. Bioremediation of pentachlorophenol by the immobilized T. LKY-7 reached an efficency of up to 90％ without toxic inhibition. The immobilized T. LKY-7 might thus be applicable for semicontinuous laccase production and bioremediation to serve inoculum for reactor system.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.503-507
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• 2002

Chitosan oligosaccharides (COSs) were prepared and fractionated into three groups of COS [a high molecular weight COS (HMWCOS), medium molecular weight COS (LMWCOS), and low molecular weight COS (LMWCOS)] according to their molecular weight, using an ultrafiltration membrane enzymatic bioreactor designed earlier [8]. Antitumor activity of these COSs was then examined against Sarcoma 180 solid (S180) or Uterine cervix carcinoma No. 14 (Ul4) tumor cell-bearing mice. Among these COSs, MMWCOS with molecular weight range from 1.5 to 5.5 kDa effectively inhibited the growth of both tumor cells in the mice. In addition, the administration of MMWCOS resulted in increased thymus weight among lymphoid organs. The mice treated with MMWCOS showed improved survival rate and larger number of survivors after 40 days of feeding. The most effective of MMWCOS far antitumor activity in the S180- or U14-bearing mice was 20 mg/kg/day or more.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.49-54
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• 2006

The present study conducted a numerical modeling on the diesel SCR (selective catalytic reduction) system using ammonia as a reductant over vanadium-based catalysts $(V_2O_5-WO_3/TiO_2)$. Transient modeling for ammonia adsorption/desorption on the catalyst surface was firstly carried out, and then the SCR reaction was modeled considering for it. In the current catalytic reaction model, we extended the pure chemical kinetic model based on laboratory-scale powdered-phase catalyst experiments to the chemico-physical one applicable to realistic commercial SCR reactors. To simulate multi-dimensional heat and mass transfer phenomena, the SCR reactor was modeled in two dimensional, axisymmetric domain using porous medium approach. Also, since diesel engines operate in transient mode, the present study employed an unsteady model. In addition, throughout simulations using the developed code, effects of space velocity on the DeNOx performance were investigated.

• Applied Biological Chemistry
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• 제49권4호
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• pp.266-269
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• 2006

송이버섯 균사체의 biomass를 위한 최적조건을 규명한 결과, 균사체 spot배양을 위한 최적 조건은 MMN배지를 사용하여 pH 5.5에서 탄소원으로 현미를 3% 첨가 하여 $24^{\circ}C$에서 35일 배양 시 최적인 것으로 판단하였으며, 송이버섯 균사체 Biomass를 위한 bioreactor의 배양 최적조건은 PDMP배지를 사용하여 $18^{\circ}C$에서 60일 배양 시 reactor의 반응은 최적의 상태를 나타낼 수 있을 것이라 판단되었다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2003년도 춘계학술발표논문집
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• pp.180-187
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• 2003

The lignin-degrading fungus Trichophyton sp. LKY-7 was immobilized in ca-alginate beads for laccase production and PCP remediation. The immobilized Trichopphyton sp. LKY-7 enabled the repeated use of this fungus for laccase production and produced high amount of laccase throughout 5 cycles incubation. As a laccase inducer oak wood meal(Quercus variabilis) seemed to be effective laccase inducer for Trichophyton sp. LKY-7, and the optimum addition amount was 1%(W/W) in glucose-peptone medium. Biotransformation of pentachlorophenol by immobilized Trichophyton sp. LKY-7 reached an efficency of up to 90% without toxic inhibition. Immobilized Trichophyton sp. LKY-7 might thus be applicable for semicontinuous laccase production and bioremediation to serve inoculum for reactor system.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 춘계학술발표회요약집
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• pp.124-124
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• 1999

An ultrasonic method is developed for the measurement of the two-phase mixture level in the reactor vessel or steam generator. The ultrasonic method is selected among the several non¬nuelear two-phase mixture level measurement methods through two steps of selection procedure. A commercial ultrasonic level measurement method is modified for application into the high temperature, pressure, and other conditions. The calculation method of the ultrasonic velocity is modified to consider the medium as the homogeneous mixture of air and steam. and to be applied into the high temperature and pressure conditions. The cross-correlation technique is adopted as a detection method to reduce the effects of the attenuation and the dif.JUsed reflection caused by suface fluctuation. The waveguides are developed to reduce the loss of echo and to remove the effects of obstructs. The present experimental study shows that the developed ultrasonic method measures the two-phase mixture level more accurately than the conventional methods do.