• 한국물환경학회지
• /
• 제21권6호
• /
• pp.664-668
• /
• 2005

An experimental study for the comparison of nitrogen and phosphorus removal efficiencies between $A^2/O$ and modified Phostrip (M-Phostrip process) were carried out with bench-scale reactors. In case of nitrogen removal efficiencies both of processes showed similar ones when influent organic loadings were high. However, M-phostrip process was more effective than $A^2/O$ at low organic loadings. This is why M-phostrip process consumes the whole mass of influent organics as a carbon sources for denitrification in anoxic reactor but the anoxic reactor of $A^2/O$ process utilizes the residual carbon followed by consumming a part of influent carbon for phosphorus release in anaerobic reactor. $A^2/O$ process required the influent COD/T-P and COD/TKN ratios were more than 56 and 10, respectively, to take place the phosphorus release in anaerobic process and phosphorus uptake in oxic process. However, the luxury uptake of phosphorus in M-phostrip process was not affected by influent COD/T-P and COD/TKN ratios and the adverse effect of nitrate in return sludge introduced to the p-stripper from the 2nd clarifier was not significant due to the configurational advantage of the p-stripper.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2013년도 춘계학술대회 논문집
• /
• pp.1373-1374
• /
• 2013

• 대한치과교정학회지
• /
• 제31권6호
• /
• pp.567-578
• /
• 2001

본 연구는 metal stripper, diamond bur, cross-cut carbide bur을 이용한 기계적 삭제방법과 산을 이용한 화학적 삭제방법 등의 서로 다른 방법으로 삭제된 치아에서 삭제방법에 따른 법랑질 표면조도의 차이를 비교하고, 삭제된 법랑질 표면에 국소적 불소도포와 교정용 전색제를 적용시 치아우식 감수성에 미치는 영향을 알아보기 위해 교정적인 목적으로 발치된 100개의 소구치를 대상으로 주사전자현미경과 레이저 형광법을 이용하여 연구한 바 다음과 같은 결과를 얻었다. 1. 치간삭제방법에 관계없이 인접면 삭제 후 법랑질 표면에 형성된 열구는 세심한 연마과정을 통해서도 제거되지 않았다. 2. 기계적인 치간삭제 방법 중에 가장 활택한 법랑질 표면조도를 보이는 군은 crosscut tungsten carbide bur로 초기삭제 후 sof-$lex^{(r)}$ disk로 연마한 군이었다. 3. 기계적 방법이나 기계적과 화학적 방법을 동반하여 치간 삭제한 모든 군의 치아우식 감수성은 대조군보다 높았다. 그러나 치간삭제 방법에 따른 치아우식 감수성의 차이는 보이지 않았다(p<0.001). 4. APF-gel 이나 sealant을 도포한 군은 치간삭제 후 다른 처치를 하지 않은 군에 비해 치아우식 감수성이 낮았다(p<0.001). 5. APF-gel을 도포한 군이 sealant을 도포한 군보다 치아우식 감수성이 낮았다(P<0.05). 결론적으로, 치간삭제 후 활택한 법랑질 표면을 얻고자 하는 노력에도 불구하고 치간삭제를 실시한 치아는 그 삭제 방법에 관계없이 정상치아에 비해 치아우식 감수성이 높았다. 따라서 치간삭제 후 주기적인 불소의 사용이 치아우식을 예방하는 최선의 방법이라고 생각된다.

• 한국물환경학회지
• /
• 제18권4호
• /
• pp.371-377
• /
• 2002

The purpose of this study is to develop effective operating process in order to achieve more suitable conditions of Anoxic-Oxic-Anoxic-Stripper(AOAS) SBR through real-time control. To improve the removal efficiency, glucose, methanol and synthetic food waste acid fermentant were added as an external carbon source, In the case of glucose and synthetic food waste acid fermentant, TN, TP were removed to average 86.9%, 73.0% respectively. Methanol was removed to average 64.6%, 55.4% respectively. The synthetic food waste acid fermentant proved to be the most efficient and allowed for the substitution of an external carbon source. The removal rate of $COD_{Cr}$, was approximately 90% at all cases. The results of the study that a correlation between ORP (Oxidation-Reduction Potential), pH and DO and nitrification or denitrification when an external carbon source is added and when it isn't was showed that ${\Delta}ORP$ is suitable parameter. ORP reacted properly to denitrification (${\Delta}ORP<-10$) and nitrification (${\Delta}ORP<0$). The use of real-time control saved anywhere between 61 and 67 minutes at the anoxic(1) stage and 26 to 52 minutes at the oxic(1) stage. When the time saved from the anoxic(1) and oxic(1) was added to the anoxic(2) stage for the removal efficiency of TN and TP increased from 0.7 to 13.9% and 12 to 35 % respectively.