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KSDeNTM 공정에서 C/P 비, SRT, 온도 및 질산염 농도가 인 제거에 미치는 영향
김병군,서인석,홍성택,김도군,천상욱 대한상하수도학회 2003 상하수도학회지 Vol.17 No.1
In this study, the effects of C/P ratio, SRT, temperature and nitrate concentration on the phosphorus removal efficiency of KSDeN™ process (KOWACO-Ssangyong DeNutrient process) was investigated with a pilot plant, which is fed with the grit chamber effluent of 'J' MWWTP (Municipal Wastewater Treatment Process). During the operating period, T-P removal efficiency was more than 80% at C/P ratio (TCOD_Cr/T-P ratio) of 35 or above, and it was higher at relatively low temperature and high C/P ratio. At SRT (Sludge Retention Time)'s of 3-28 days, phosphorus removal efficiency increased up to 90% until the SRT reached 20 days. The phosphorus removal efficiency decreased rapidly with more than 20 days of SRT, which showed that the optimal SRT is 20 days for the T-P removal of KSDeN™ process. Effluent T-P concentration increased with increasing temperature. It is considered that the competition on organic compounds between PAOs (Phosphorus Accumulating Organisms) and denitrifiers resulted in lowering T-P removal by activating nitrifiers at 15℃ or above. The release of phosphorus was influenced by nitrate concentration in anaerobic/anoxic tank. When the nitrate concentration was higher than 2 ㎎/L, the release of phosphorus was disturbed by denitrifiers. SCOD and PO^3-_4-P profile with each reactors of KSDeN™ process showed typical behavior of phosphorus release and luxury uptake by PAOs.
김도군,천상욱,김병군,서인석,박철휘,김성준,류수현 대한상하수도학회 2002 상하수도학회지 Vol.16 No.4
Intermittent aeration processes have been much of interest as an excellent alternative for nutrients removal for upgrading secondary wastewater treatment plants, with minimum modification. Also, operational flexibility of those proposes a good opportunity for newly planed plants. Here, a pilot study was conducted to evaluate the performance of a continuous flow intermittent aeration process (KSDeN^TM process). The influent was collected at the effluent channel of the grit chamber of a large sewage treatment plant. The influent characteristics with standard deviation were 243.2±170.9mg/L for TCOD_cr, 47.5 13.9mg/L for T-N, 8.4±8.3mg/L for T-P and 5.2±1.8 for C/N ratio. Effluent of 1^st sedimentation tank was 208.2±87.6mg/L for TCOD_cr, 35.0±10.3mg/L for T-N, 4.8±1.9mg/L for T-P and 6.1±2.3 for C/N ratio. The average removal efficiencies of TCOD_cr, T-N and T-P were 93.6, 77.0 and 86.4% and effluent TCOD_cr, T-N and T-P concentrations were 12.5, 9.2 and 0.7mg/L respectively, satisfying regulatory limits. Alkalinity deficiency was not observed during the oxic periods, which is one of the special features of an intermittent aeration process. The results showed higher COD, T-N and T-P removal efficiencies and stability with varying influent conditions, compared to other conventional fixed phase nutrients removal processes.
이송우,나영수,김도한,류동춘,최동훈,류병순,송승구 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.1
본 연구는 무연탄으로 활성탄을 제조할 경우 성형이 세공특성에 미치는 효과를 고찰한 것이다. 3가지 다른 방법으로 활성탄(파쇄형 활성탄, 압축성형 활성탄, 압축성형 활성탄)을 제조하여 특성을 비교했다. 이중에서 25%의 콜타르와 7%의 물을 혼합하여 압출 성형한 활성탄이 비표면적, 세공부피, 그리고 경도에서 가장 좋은 물성을 나타내었다. 압축 및 압출 성형체의 표면은 무연탄 원탄과는 달리 무연탄 분말이 바인더와 혼합되어 있으므로 매우 거친 상태를 나타내었고, 활성화시 거칠게 형성되어 있는 입자사이로 활성화제인 수증기가 쉽게 침투하여 많은 세공을 형성시킴을 알 수 있었다. 이렇게 형성된 세공을 통해 수증기 활성화반응이 잘 일어나 직경 3,000-50,000Å 범위의 거대세공이 발달하였다. 파쇄형 활성탄에 비해 약 2배의 거대세공(macropore)부피를 가지고 있었으며 경도도 30%에서 95% 이상으로 상승되었다. This study was to investigate the effect of granulation process on pore characteristics in manufacturing anthracitebased activated carbons. The activated carbons were made by three different methods to compare characteristics: the crushed activated carbon, the compressed activated carbon, and the extruded activated carbon. Among these activated carbons, the extruded activated carbon using a binder that consists of 25% coal tar and 7% water showed the best characteristics in specific surface area, pore volume, and hardness. Since the compressed and the extruded substances had coarser surfaces than a raw material, steam could penetrate easily through particles and produce macropores especially in the diameter ranges of 3,000-50,000Å during activation process. The extruded activated carbon showed about twice more macropore volumes than the crushed activated carbon and the hardness was increased from 30% up to 95%.
Interaction between odontoblast and bio-calcium phosphate cement reinforced with chitosan
Byung-Do Chun,Sung-Won Kim,Sung-Tak Lee,Tae-Hoon Kim,Jung-Han Lee,Gyoo-Cheon Kim,Yong-Deok Kim,Uk-Kyu Kim 대한구강악안면외과학회 2011 대한구강악안면외과학회지 Vol.37 No.5
Purpose: Calcium phosphate cement (CPC) is one of many useful materials for restoring tooth defects, periodontium and maxillofacial area. Chitosan is a biodegradable material that has been shown to promote the growth and differentiation of osteoblasts in culture. This study examined the interaction between odontoblasts and bio-calcium phosphate cement reinforced with chitosan. Materials and Methods: 5×10 3 odontoblastic cells were seeded into each well. Various concentrations of bio-calcium phosphate cement reinforced with chitosan (10, 20, 50, 100, 200, 500 μg/ml, 1, 2, 4 mg/ml) were diluted and added to the wells. The well was incubated for 24 h, 48 h and 72 h. After incubation, the number of cells was assessed to determine the cell viability. A cytokinesis-block micronucleus assay and chromosomal aberration test were carried out to estimate the extent of chromosomal abnormalities. Microscopic photographs and RT-PCR were performed to examine the adhesion potential of bio-calcium phosphate cement reinforced with chitosan. Results: Bio-CPC-reinforced chitosan did not show significant cytotoxicity. The number of damaged chromosomes in the cells treated with BioCPC-reinforced chitosan was similar to that in the control cells. There was no significant increase in the number of chromosomal aberrations in the Bio-CPC reinforced chitosan exposed cells. Microscopic photographs and RT-PCR confirmed the adhesive potential of bio-CPC reinforced chitosan to odontoblasts. Conclusion: Bio-CPC-reinforced chitosan did not affect the odontoblastic cell viability, and had no significant cytotoxic effect. Bio-CPC-reinforced chitosan showed adhesive potential to odontoblasts. These results are expected form the basis of future studies on the effectiveness of dental restorative materials in Bio-CPC reinforced with chitosan.
전병도(Byung-Do Chun),이재열(Jae-Yeol Lee),김용일(Yong-Il Kim),허지예(Ji-Yae Heo),황대석(Dae-Seok Hwang) 대한구강악안면외과학회 2010 대한구강악안면외과학회지 Vol.36 No.6
Ameloblastoma is a common odontogenic tumor originating from the dental lamina, reduced dental epithelium and rests of Malassez, and represents 10% of all odontogenic tumors of the jaw. Unicystic ameloblastoma is normally encountered in young patients, and often occurs in the mandible, and is particularly associated with an impacted tooth. We encountered an unicystic ameloblastoma arising from a dentigerous cyst after the treatment of a radiolucent lesion on the mandible.
Development of a High Speed Induction Motor for Spindle Systems
Do-Kwan Hong,Jae-Hak Choi,Dong-Jun Kim,Yon-Do Chun,Byung-Chul Woo,Dae-Hyun Koo IEEE 2013 IEEE transactions on magnetics Vol.49 No.7
<P>This paper deals with the analysis techniques of a high speed and high efficiency 10 kW, 30 000 rpm rated induction motor. The induction motor has been analyzed by the time-varying magnetic finite element method and the test results show that there is a possibility that the motor could be used in a high speed spindle system application. All performances of the prototype are successfully verified. All analysis techniques are introduced to develop a high speed and high efficiency induction motor made by copper die casting. The analysis techniques are composed of magnetic analysis, structural analysis, critical speed analysis, unbalance response analysis and computational fluid dynamics (CFD). CFD simulation results are compared with the experiment, and are within a 5% deviation.</P>