• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.290-295
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• 2020

In this study, the optimum conditions were established for anthocyanidin extraction from sweet potato tips and tubers. The dependent variables of ethanol concentration (X1), citric acid concentration (X2), and extraction temperature (X3) were designed using a central composite design. All three variables significantly affected anthocyanidin extraction, and the influence of X1 was greater than that of X2 and X3. The highest anthocyanidin content in tips and tubers were 26.58±0.07 and 117.32±0.39 mg/100 g at 50% (X1), 0.3% (X2), and 50℃ (X3), respectively. The optimal extraction conditions for the tips were 56.10% (X1), 0.25% (X2), and 52.24℃ (X3) and tubers were 55.08% (X1), 0.30% (X2), and 53.06℃ (X3). The predicted values under optimal extraction conditions were 27.45 and 119.61 mg/100 g, and the experimental values were 27.09±0.11 and 118.72±0.67 mg/100 g, respectively. The extraction conditions were validated by comparing the predicted and actual values with those of 98.69 and 99.26%, respectively.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.11a
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• pp.141-141
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• 2001

사이즈 프레스용 전분은 주로 산화전분이 이용되고 있으며, 전분업체에서 공급되는 것과 제지공장에서 자가변성으로 제조하여 이용하는 것으로 나눌 수 있다. 자가변성의 경우 경제적 측면에서 원가절감이 가능한 장점이 있는 반면 전분 품질이 다소 미흡한 단점이 있다. 자가변성 산화제로는 APSCAmmonium persulfate), 효소 등이 이용된다. 효소는 APS에 비해 전분 분자 내의 1,4결합만을 가수분해 시키고 점도안정성과 전분 용액 색상이 양호한 특성을 보인다. 또한 온도/농도/점도 등의 상관성을 자유롭게 이용하여 요구하는 전분 용액 품질을 얻을 수 있다. 제지용 전분 산화용으로는 주로 알파 -아밀라아제가 이용된다.본 실험은 산화전분을 효소변성을 이용한 생전분으로 가능성을 알아보고자 진행되었다. 일차적으로 실험실에서 하였고, 몇 차례의 mill trial을 통해 효소변성 전분 적용을 최적화하고자 하였다. 실험실적으로 효소변성을 위한 반응조건으로 온도, 시간, pH, 투입량 등을 설정하였 고, 각 조건별로 제조된 전분 용액의 점도를 측정하여 효소 반응성을 평가하였다. 실험 결과 전분 용액의 점도는 낮았고, 점도 안정성 또한 양호한 수준을 보였다. Cooking농 도는 20%로 하였으나 보다 고농도 cooking의 가능성을 확인할 수 있었다. 시트 물성도 전반적으로 산화전분 대비 대등한 수준을 나타내었다. Mill trial은 무림제지에서 실시하였고 사이즈 프레스 조제식을 이용하였다. 전분 농도는 초기에 20%로 시작하여 30%까지 올려서 trial을 실시하 였고, 그 외 작업조건들은 산화전분 적용 시와 동일하게 하였다. 효소 반응시간으로 인해 cooking시간이 다소 많이 걸렸으나 전반적인 조제 작업은 큰 문제 없이 이루어졌고, 효소변성 전분 용액의 점도는 낮은 수준으로 유지되었다. 사이즈 프레스 작업성이나 시 트 물성도 산화전분 적용 시와 대등한 수준을 보였으나, 전분 차이로 인한 색상 차이로 부가적인 염료 조정이 이루어졌다. 한편 폐수부하 증가를 우려하였으나, 이에 따른 문제는 크게 발생되지 않았다.

• Analytical Science and Technology
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• v.25 no.3
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• pp.164-170
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• 2012

Cyanoacrylate fuming mehod is effective for latent fingerprints developing on non-porous surfaces. In this study, we investigated optimal conditions for latent fingerprint development using cyanoacrylate fuming method in vacuum chamber. The effects of temperature, relative humidity, fuming method and processing time were checked throughly. The amount of evaporated cyanoacrylate was increased at higher temperature, but cyanoacrylate polymerization on the fingerprint ridge was best at $30^{\circ}C$. With a relative humidity of 40% to 50% conditions, good quality of fingerprints were developed. If a relative humidity is lower than 30% or higher than 60%, polymerization rate of cyanoacrylate monomers on the fingerprint ridge was decreased. It was identified that application of $OMEGA-PRINT^{TM}$ dispersal pad or cotton ball with sodium hydroxide fuming method in vacuum chamber was more effective than natural fuming method. We found that cyanoacrylate processing time in vacuum chamber did not have more significant than relative humidity.

• KSBB Journal
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• v.9 no.2
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• pp.127-132
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• 1994

A new method of fructooligosaccharides production was investigated by an amyloglucosidase using sucrose as a substrate. Optimum reaction conditions were as follows: sucrose concentration, 700g/$\ell$; pH 5.5; temperature, $55^{\circ}C$; enzyme dosage, 48 units per gram sucrose. At the optimized reaction conditions, 41.5% of fructooligosaccharides were produced after 25 hours. A hydrolyzing activity was stronger than transfructosylting activity at low sucrose concentrations, resulting in low production rate of fructooligosaccharides. The optimum pH and temperature in both transfructosylating(pH 5.5, $60^{\circ}C$) and hydrolyzing activity(pH$4.75^{\circ}C$)were significantly different from each other. The amyloglucosidase also utilized fructooligosaccharides as a substrate and glucose seemed to be an inhibitor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.787-794
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• 2010

This paper aims to evaluate the effect of each material ingredient on mechanical and dynamic performance and to determine an optimal mixing condition of a rubber granule layer. To minimize the required number of tests, the test matrix was established by using the design of experiments (DOE). The tensile tests were then performed to identify the mechanical properties. Also, to evaluate the dynamic performance that the IAAF has required for athletics tracks for athletes' safety and balance, a series of impact tests were performed by using the so-called the "artificial athlete" machine. Finally, the response surface methodology was used to decide the optimal mixing conditions needed to achieve a high level of mechanical properties and dynamic performance.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.172-178
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• 2020

In this study, the optimization of the biodiesel production process from waste oil using microwave with response surface methodology (RSM) was conducted. The microwave irradiation time and power in addition to the alcohol/oil mole ratio were chosen as process parameters. Also the fatty acid methyl ester (FAME) content (over 96.5%) and kinematic viscosity (1.9~5.5 cSt) were selected as response values. From basic experiments, the range of quantitative factors were set as following; 4~6 min, 400~600 W, and 7~9 for the microwave irradiation time and power, and alcohol/oil molar ratio, respectively. The optimum conditions for the methanolysis were 5.0~5.1 min, 481.3~525.5 W, 7.9~8.4, and 2.0 or 3.0 mg KOH/g for the microwave irradiation time and power, methanol/oil molar ratio, and each acid value, respectively. The FAME content and kinematic viscosity were predicted as 97.49~96.34% and 4.01~4.12 cSt, respectively, under the condition above. Under the optimum experimental conditions, the results showed that the FAME content and kinematic viscosity of 97.82~96.42% and 4.07~4.16 cSt, respectively were measured and the mean error rates were 0.22% and 0.98%, respectively.

• Applied Chemistry for Engineering
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• v.35 no.4
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• pp.316-320
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• 2024

To optimize the emulsion stability and antibacterial activity against Escherichia coli (E. coli) of cosmeceuticals using Scutellaria baicalensis extracts and olive wax as natural emulsifiers, we conducted a study. The independent variables were the amounts of Scutellaria baicalensis extracts and olive wax added. The response variables included the emulsion stability index (ESI) of the cosmeceuticals product and the inhibition diameter against E. coli. Through central composite design-response surface methodology (CCD-RSM), we obtained a statistically significant and reliable regression equation within a 95% confidence interval. By optimizing multiple responses, we determined that the optimal emulsification conditions that satisfied both ESI and E. coli inhibition diameter were 3.7 wt% of Scutellaria baicalensis extracts and 2.7 wt% of olive wax. The predicted ESI and E. coli inhibition diameter were 97.9% and 9.7 mm, respectively. When actual experiments were conducted under the optimal conditions, the measured ESI and E. coli inhibition diameter were 95.0% and 9.4 mm, respectively, with an average error rate of 3.2 ± 0.4%.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.540-544
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• 2008

In this study, response surface methodology was employed in order to optimize the limonin and nomilin extraction conditions from citron seed. The independent variables were extraction temperature, extraction time, and shaking velocity. The yield of limonin and nomilin increased with increased extraction temperature and time. The extraction effects on the limonin and nomilin were higher at extraction temperature (p<0.01). The predicted extraction conditions were validated through actual experiments. The predicted conditions were as follows: $49.7^{\circ}C$ of extraction temperature, 3.3 hr of extraction time, and 400.6 rpm of shaking velocity for the maximum limonin contents (353.9 mg/100 g) and $50.3^{\circ}C$, 3.5 hr, and 399.9 rpm for the maximum nomilin contents (214.5 mg/100 g). The experimental values of limonin and nomilin contents at the predicted conditions were 338.8 and 219.5 mg/100 g, respectively. The predicted values at the optimized conditions were acceptable when compared to the experimental values.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.9
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• pp.924-933
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• 2007

An impeller is a important part of turbo-machinery. It has a set of twisted surfaces because it consists of many blades. Five-axis machining is required to produce a impeller because of interference between tool and workpiece. It can obtain good surface integrity and high productivity. This paper proposes finish cutting method for machining impeller with 5-axis machining center and optimization of cutting condition by response surface method. Firstly, cutting methods are selected by consideration of operation characteristics. Secondly, response factors are determined as cutting time and cutting error for prediction of productivity. Experiments are projected by central composite design with axis point. Thirdly, regression linear models are estimated as single surface in the leading edge and as dual surface in the hub surface cutting. Finally, cutting conditions are optimized.

• ETRI Journal
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• v.13 no.2
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• pp.91-98
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• 1991

저에너지 광이온선 (broad ion beam) 을 이용한 건식식각과 박막증착에 있어서 이온선 및 증착의 조건들에 따른 영향을 살펴보았다. 저에너지 광이온선은 화합물반도체 공정 및 고융점금속의 증착, optical coating, cosputter 에 의한 초전도물질합성 등 사용범위가 넓다. 단일이온선증착과 cosputter 의 경우에 근사수식과 실험치로서 증착비 및 막의 균일도를 최적화하는 target, 웨이퍼, 이온원 사이의 기계적 설계에 대해 고찰하였다. 저에너지 이온선의 이온과 target 원자 그리고 스퍼터된 이온과 시편원자와의 물리적, 화학적 반응기구는 반응성 이온과 보조 이온선 등의 다양한 기술에 응용될 수 있을 것으로 기대된다.