• Resources Recycling
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• v.28 no.2
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• pp.23-30
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• 2019

An color sorting technique was introduced to recycle End-of-life automobile shredded bumpers. The color sorting is a innovate method of separating the differences in the color of materials which are difficult to separate in gravity and size classification by using a camera and an image process technique. Experiments were planned and optimal conditions were derived by applying BBD (Box-Behnken Design) in the reaction surface method. The effects of color sensitivity, feed rate and sample size were analyzed, and a second-order reaction model was obtained based on the analysis of regression and statistical methods and $R^2$ and p-value were 99.56% and < 0.001. Optimum recovery was 94.1% under the conditions of color sensitivity, feed rate and particle size of 32%, 200 kg/h, and 33 mm respectively. The recovery of actual experiment was 93.8%. The experimental data agreed well with the predicted value and confirmed that the model was appropriate.

• Applied Chemistry for Engineering
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• v.35 no.3
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• pp.222-229
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• 2024

The use of low-toxic, hypoallergenic, and environmentally friendly natural pigments has increased. With growing interest in health, research on natural extracts containing beneficial substances for the human body is actively underway. In this study, natural pigments were extracted from sprout barley using a solvent extraction method and CCD-RSM was used to optimize the extraction process. The experiment's independent variables included extraction temperature, alcohol/ultra-pure volume ratio, and extraction time. The response variables were set to achieve a target chromaticity (L = 45, a = -35, b = 45), and to maximize DPPH radical scavenging activity evaluating the antioxidant capacity. The statistical significance of the main effect, interaction effect, and effect on the response value was evaluated and analyzed through the F and P values for the regression equation variables calculated using RSM optimization. Additionally, the reliability of the experiment was also confirmed through the P values of the probability plot graph. The extraction conditions for optimizing the four reaction values are 76.1 vol.% alcohol/ultra pure water volume ratio, an extraction temperature of 52.9 ℃ , and an extraction time of 49.6 min. Under these conditions, the theoretical values of the reaction values are L = 45.4, a = -36.8, and b = 45.0 DPPH radical scavenging activity = 30.9%. When the actual experiment was conducted under these optimal extraction conditions and analyzed, the measured values were L = 46.2, a = -36.1, and b = 48.2, and antioxidant capacity = 31.1% with an average error rate of 2.9%.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.622-627
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• 2009

The objectives of this study were to evaluate a protease suitable for the enzymatic hydrolysis of a snow crab processing by-product (SPB) and to optimize the hydrolysis conditions using response surface methodology (RSM). The SPB was hydrolyzed at $50^{\circ}C$ and pH 7.0-7.2 to obtain various degree of hydrolysis (DH) using Flavourzyme at an enzyme/substrate (E/S) ratio of 3.0%. The reaction progress curve exhibited an initial fast reaction rate followed by a slowing of the rate. The DH was increased to 30% at 90 min with a final DH 32 to 36%. A central composite experimental design having three independent variables (reaction temperature, reaction time, and E/S ratio) with five levels was used to optimize the enzymatic hydrolysis conditions. Based on the DH data, the optimum reaction conditions for the enzymatic hydrolysis of the SPB were a temperature of $51.8^{\circ}C$, reaction time of 4 hr 45 min, and an E/S ratio of 3.8%. It was demonstrated that the enzymatic hydrolysate of SPB could be used as a flavoring agent or a source of precursors for the production of reaction flavors.

• Corrosion Science and Technology
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• v.21 no.5
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• pp.360-371
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• 2022

Electropolishing has various parameters because an electrochemical reaction is applied. Accordingly, experiments to determine factors and levels of electropolishing conditions are in progress for various materials. The purpose of this investigation was to optimize conditions for electropolishing using the taguchi method for UNS S31603. Factors such as electrolyte composition ratio, electrolyte temperature, and electropolishing process time were selected. Electropolishing was optimized using analysis of variance (ANOVA), signal-to-noise ratio (the smaller the better characteristics), and surface analysis. Results of ANOVA revealed that only the electrolyte composition ratio among factors was effective for surface roughness. As a result of statistical analysis of the signal-to-noise ratio, the highest signal-to-noise ratio was calculated under electropolishing conditions with sulfuric acid and phosphoric acid ratio of 4:6, an electrolyte temperature of 75 ℃, and electropolishing process time of 7 minutes. In addition, the surface roughness after electropolishing under the above conditions was 0.121 ㎛, which was improved by more than 88% compared to mechanical polishing.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.85-91
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• 2020

Polyphenols extraction conditions including extraction solvent, temperature, pH and time were optimized for the development of functional bio-convergence materials using non-edible parts of Aronia melanocarpa including its berry. Water, ethanol, and methanol were used for the extraction of polyphenol from aronia leaves, stem and twigs. Water was selected as an extraction solvent because water gave the highest extraction yields. Among the non-edible parts, aronia leaves had the highest total polyphenol content. The polyphenol extraction conditions from aronia leaves were statistically optimized using a experimental design method: reaction time of 4.5 h, extraction temperature of 79.3℃, and pH 7.2. These optimized extraction conditions could be used for the production of functional bio-material.

• Journal of Life Science
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• v.12 no.6
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• pp.765-768
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• 2002

Enantioselective hydrolysis of racemic styrene oxide by Rhodotorula sp. CL-82 was investigated. Reaction conditions including pH, temperature, and volume ratio of organic cosolvent were optimized using response surface methodology, and the optimal conditions of pH, temperature, and the volume ratio of cosolvent were determined to be 7.64, $33.26^{\circ}C$, and 3.09 %(v/v), respectively. Chiral (S)-phenyl oxirane could be obtained with high enantiomeric purity (ee ＞ 99%) and 20% yield (theoretical yield ＝ 50%) at the optimal rendition.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.429-435
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• 1989

A bacterial strain of Brevibaterium sp. CH1 was isolated and used to produce an enzyme (nitrile hydratase) necessary for earring out the bioconversion of acrylonitrile to acrylamide. The culture and reaction conditions, and medium optimization were studied for the strain. The conversion yield was nearly 100％ with a trace amount of acrylic acid produced. The strain showed strong activity of nitrile hydratase toward acrylonitrile and extremely low activity of the amidase toward acrylamide. We sought optimum culture conditions for the formation of nitrile hydratase by Brevibacterium sp. CH1. The effects of temperature and pH on the activity of free and immobilized tells were investigated. The nitrite hydratase of Brevibacterium sp. CH1 acted not only on various aliphatic nitrites such as acrylonitrile, propionitrile and acetonitrile, but also on aromatic nitrile as nicotinonitrile.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.80-84
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• 2014

The process of petroleum involves in a large amount of oily wastewater that contains high levels of chemical oxygen demand (COD) and toxic compounds. So they must be treated before their discharge into the receptor medium. In this paper, wet peroxide oxidation (WPO) was adopted to treat the oily wastewater. Central composite design, an experimental design for response surface methodology (RSM), was used to create a set of 31 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the COD removals. The experimental results show that WPO could effectively reduce COD by 96.8% at the optimum conditions of temperature $290^{\circ}C$, $H_2O_2$ excess (HE) 0.8, the initial concentration of oily wastewater 3855 mg/L and reaction time 9 min. RSM could be effectively adopted to optimize the operating multifactors in complex WPO process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.554-560
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• 1989

An optimal design technique is used as a systematic approach to analyze the worst case of a circulating type ropeway for a given geometry and operating conditions. Worst case is meant here the case when the positions and weights of the cars are so conditioned that the minimum of all the reaction forces between the main rope and the towers is minimum. In the course of this study, a general theory for the deflections and tensions of the main rope were also derived taking into account of the variation of the weights and positions of the individual cars. And through an analysis of example ropeways, some general conditions for the worst case are deduced.

• Journal of Applied Biological Chemistry
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• v.63 no.1
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• pp.111-116
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• 2020

Total polyphenol contents, flavonoid contents, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activities of ethanol extracts of 20 herbal plants (sage, turmeric, mace, bayleaf, fenugreek, oregano, blackpepper, whitepepper, clove, marjoram, cinnamon, coriander, basil, dillseed, mustard, cadamon, thyme, celery, rosemary, cumin) were analyzed for the screening of high flavonoid-containing plant resource. Thyme extract, showing the highest flavonoid content and a high degree of antioxidant activity, was selected as a bioactive cosmetic material. The total polyphenols and flavonoids contents of thyme extracts were measured as 6.90 mg chlorogenic acid equivalent (CAE)/100 g and 1.71 mg naringin equivalent (NE)/100 g, respectively, and DPPH radical scavenging activities was 90%. Among the tested organic solvents, hexane gave the highest extraction yield. Thus hexane was selected as the most suitable solvent for the extraction of thyme. Response surface method was used to obtain optimized extraction conditions for thyme: reaction temperature of 35.9 ℃, raw material to hexane ratio of 1.63:25 (w/v), and reaction time of 192 min. These predicted extraction conditions was validated by a total flavonoid extraction experiment showing a value equivalent to 96.3% of the predicted total flavonoid content. It is expected that the optimized solvent extraction conditions could be used for the production of flavonoid using thyme.