• 한국환경보건학회지
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• 제30권5호
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• pp.366-373
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• 2004

Food waste is becoming by environmental problem nowdays increasing festinately in Korea during past 10 years. Food waste collected from garbage trucks that is offered in S municipal government that food waste mixs enough, and sewage sludge collected in the country. Composting experiment conditions achieved in the mixture ratio rate that food waste and sewage sludge are each 10:90, 30:70, 50:50, 60:40, 70:30 and 90:10 $wt\%$. The fermentation temperature was $18{\sim}22^{\circ}C$ at the beginning, and then it was sharply increased to $44{\sim}66^{\circ}C$ up to 1 day after fermentation, which was maintained for more than 3 days. Then, it was slowly decreased to $18{\sim}25^{\circ}C$ up to 8 days after fermentation, which was maintained all the time. It could be known from examiation of various conditions, including reaction rate, salinity. carbon/nitrogen(C/N) ratio, temperature, organic substance, etc.. Optimum mixture ratio rate of composting using food waste and sewage sludge was 60:40 $wt\%$.

• 한국환경과학회지
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• 제11권2호
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• pp.93-102
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• 2002

Using a simple continuous optical technique, coupled with measurements of zeta potential, the flocculation characteristics of kaoline suspensions of different content(15, 35 and 55 NTU) by several cationic polyelectrolytes, has been examined. The optimum mixing is obtained under a constant stirring of 200 rpm, differently from a general flocculation test. The charge density of a polyelectrolyte is important in determining the optimum dosage and in the removal of kaoline particles. The optimum dosage is less for the polyelectrolyte of higher charge density and is the same regardless of kaoline content. At the dosage, the removal of kaoline particles is higher for the polyelectrolyte of higher charge density and zeta potential of kaoline particles reaches to near zero. The rate of adsorption and flocculation rate have been found to be affected by charge density and molecular weight of a polyelelctrolyte and the content of kaoline particles.

• 한국식품조리과학회지
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• 제22권1호
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• pp.1-11
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• 2006

To determine the optimal mixing conditions of Noni jelly, samples were prepared with various compounding ratios of Noni juice(120, 160, 200, 240 and 280 g), gelatin(12, 16, 20, 24 and 28 g) and sucrose(80, 100, 120, 140 and 160 g) using a central composite design. Physical and sensory evaluations were performed and the results analyzed using response surface methodology. The optimum mixing rate satisfying sensory items was Noni juice 192 g, gelatin 18.25 g and sucrose 135 g.

• 전자공학회논문지D
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• 제35D권8호
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• pp.69-75
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• 1998

We demonstrate wavelength conversion of 2.5Gb/s optical signals by four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). We investigate the effect of input pump and signal powers on the coversion efficiency, optical signal-to-noise ratio (OSNR) and extinction ratio to be a measure of performance in a wavelength converter. As a result, we show that the maximum bit error rate (BER) performance can be obtained by co promising among high-vonversion efficiency (minimum Pprobe), high-OSNR (maximum Pprobe) and low-cross-gain saturation effects (Pprobe kept at least 6dB weaker than Ppump). In our experiment, we obtain optimum performance at +3 dBm pump power and -6dBm signal power. The power penalty incurred in the wavelength conversion can be minimized by careful selection of the input pump and signal powers. We show that about 0.5dB power penalty for 3.2nm wavelength coversion at 10-10 BER is achievable.

• Archives of Pharmacal Research
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• 제27권3호
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• pp.351-356
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• 2004

A transdermal preparation containing diclofenac diethylammonium (DDA) was developed using an O/W microemulsion system. Of the oils tested, lauryl alcohol was chosen as the oil phase of the microemulsion, as it showed a good solubilizing capacity and excellent skin permeation rate of the drug. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant and cosurfactant for microemulsion formation, and the effect of these additives on skin permeation of DDA was evaluated with excised rat skins. The optimum formulation of the microemulsion consisted of 1.16% of DDA, 5% of lauryl alcohol, 60% of water in combination with the 34.54% of Labrasol (surfactant)/ethanol (cosurfactant) (1:2). The efficiency of formulation in the percutaneous absorption of DDA was dependent upon the contents of water and lauryl alcohol as well as Labrasol: ethanol mixing ratio. It was concluded that the percutaneous absorption of DDA from microemulsions was enhanced with increasing the lauryl alcohol and water contents, and with decreasing the Labrasol:ethanol mixing ratio in the formulation.

• 펄프종이기술
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• 제46권6호
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• pp.34-40
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• 2014

Wood fibers for medium density fiberboard (MDF) was used in the filler layer of the white duplex board for increasing thickness and bulk of the board. The MDF fibers and the old corrugated container (OCC) furnish were refined, and mixed together to form paperboard. At optimum mixing ratios and refining degrees, stiffness and tensile strength of the MDF fiber-containing board were higher than those of the board with 100% OCC. It was found that there was possibility to reduced basis weight of the filler layer down to 90% of the all OCC furnish by judicious selection of the mixing ratio and the refining method of the MDF fibers. Drainage rate increase and potential drying energy savings were additional benefits.

• 대한환경공학회지
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• 제30권11호
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• pp.1139-1145
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• 2008

응집-막분리 공정의 적용시 전처리 응집공정에서 응집조건에 따라 발생하는 플럭 생성특성을 파악하고 생성된 플럭 특성에 따른 막투과 플럭스의 영향을 살펴본 결과 인공시수와 낙동강 원수에서 전처리 응집공정을 적용시 급속교반 후 용존성 유기물질(자연유기물질)이 미세 플럭의 형성으로 인하여 입자상 유기물질로 전환이 발생하였으며 급속교반초기 10초 사이에 용존성 유기물이 입자상 물질로 전환되었다. 또한 응집제 주입량이 0.025 mM as Al (7.5 mg/L Alum) 이었을 경우 입자 전환율 K값이 크게 나타나고 있었으나 0.05 mM (15 mg/L Alum)이상으로 응집제 주입량이 증가할 경우 K값은 감소하였으며 0.15 mM까지 유사한 값을 보이고 있었다. 낙동강 원수를 이용하여 전처리 공정으로 응집 공정을 적용시 UF 단독공정에 비하여 투과 flux 감소는 상당히 낮게 나타났으며 투과 flux 변화는 응집공정에 의하여 형성되는 입자크기 분포에 의존하였으며 응집조건에 따른 투과 flux 실험결과 급속교반-UF공정과 급속교반-완속교반-UF공정의 투과 flux는 유사하게 나타났다. 막의 재질에 따른 투과 flux 실험결과 소수성 재질의 막에 비하여 친수성 재질의 막이 투과 flux가 높게 유지되었으며 응집제 자체의 금속성분에 의한 막오염 영향은 나타나지 않았다.

• 공업화학
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• 제10권4호
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• pp.586-591
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• 1999

유연탄과 무연탄 및 유, 무연탄의 연소특성을 해석하기 위하여 내경 0.109 m의 유동층반응기에서 회분석 석탄주입에 따른 유동화특성과 연소특성 실험을 수행하였다. 온도변화곡선, 압력요동특성치를 이용하여 회분식유동층에서 유연탄과 무연탄 및 혼합석탄의 연소특성을 측정하였다. 유연탄과 무연탄의 입자크기, 두 석탄의 혼합비, 유동화매질의 입자크기에 따른 영향을 고찰하였다. 유연탄과 무연탄의 혼합연소시 무연탄의 혼합비가 30 %인 경우가 유연탄의 연소속도 및 연소거동이 최적으로 나타났다. 저품위 고회분 무연탄의 경우 유동화특성보다 연소특성에 의한 영향이 더욱 크게 나타났다. 또한 유동층의 유동화 특성에 의하여 연소거동이 변화됨을 알 수있었다.

• 한국환경과학회지
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• 제11권1호
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• pp.69-74
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• 2002

This study was performed to evaluate an applicability of the SMMCMAS system for reuse of the sewage from spa area and was operated to HLR(Hydraulic loading rate) of 211.3 to 126.8 $\ell$/㎥/d. The operating HRT(Hydraulic retention time) ranges were 2.5 to 1.5 hours. Conclusions are as follows; At the optimum HLR of 158.5 $\ell/\m^2$/d (HRT of 2.0 hours), the maximum BOD removal efficiency was 94% and the effluent BOD concentration was 1.1mg/$\ell$ in result. As the HLR was increased to 211.3 $\ell/\m^2$/d, BOD removal efficiency was decreased to 75% and BOD removal efficiency was also reduced to 74% at lower HLR of 126.8 $\ell/\m^2$/d. It shows that the maximum BOD removal efficiency occurs at an optimum HLR value and that the removal efficiency decreases when the HLR is either higher or lower than the optimum value. Sludge production rates were ranged 0.01 to 0.24gVSS/gBODrem/d and accomplished to 0.01gVSS/gBODrem/d at the optimum HLR of 158.5 $\ell/\m^2$/d.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.262-268
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• 1998

This research is to examine the selected method of optimal mixing proportion and cost analysis in the super flowing concrete. As confined water $ratio($\beta_p$)$ and K is introduced, itis to establish optimal mixing design of super flowing concrete according to the steps of paste, mortar and concrete. From paste and mortar test, it was led to $$\beta_p$$ and $K_p$satisfying the optimum condions depending on the kinds of binders. Then $$\beta_p$$ and $K_p$ is reflected to the mix condition of super flowing concrete. The result of test, the mix condition of super flowing concrete satisfied the quality performance of concrete with adjustment of additional rate of the superplasticizer. Besides, in case of design strength $350kg/\textrm{cm}^2$ of concrete, material cost in super flowing concrete is able to be reduced 5~16% in replacement of fly ash 30% in ordinary portland cement and slag cement.