• Journal of the Korean Society for Heat Treatment
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• v.36 no.1
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• pp.33-39
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• 2023

In this study, the effect of mixing condition of raw material powders possessing various particle size and particle size distribution on thermite reaction efficiency was investigated. When fine raw powders are used, rather the reaction yield tends to decrease due to agglomeration. In contrast, coarse raw powders make deteriorate the contact area between raw material powders containing Al reducing agent. To ensure the optimal thermite reaction efficiency, it is required to optimize a mixture condition of raw material powders prior to thermite reaction. From the current experiment, the maximum thermite reaction efficiency is 77%, which came from Nb₂O₅ + NiO +Al mixtures with size distribution from 9.25 to 22.63 ㎛.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.101-105
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• 2011

Determination of ultrasonic frequency and experimental design approach to optimization of ultrasonic soil-washing process for remediation of diesel contaminated soil were investigated. Ultrasonic frequencies of 35, 72, and 100 kHz were used for determination of optimal frequency. $MINITAB^{(R)}$ program was used for experimental design of optimal washing condition. The optimal ultrasonic frequency was 35 kHz. Even though the number of cavitation bubble is little, however cavitation bubbles involving larger energy compared with high frequency was generated. Therefore, the removal efficiency at low frequency was higher than at high frequency. However the input energy has to be considered when the process is applied. The statistical tests from a factorial experiment shows that the application of ultrasound and mechanical mixing are the most important factor for design of an ultrasonic soil washing process. The lab-scale experiments are required to get the optimal condition of ultrasound and mechanical mixing for application of ultrasonic soil washing process.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.535-544
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• 2021

When baking, the proper blending or mixing of materials will affect the quality of the product. The mixing strength is important when establishing the optimal conditions for batter, and control of the mixing condition is accordingly an important factor. This study investigated the effects of the mixing speed and time on the quality characteristics of a gluten-free type of rice batter. The batter samples manufactured for this purpose are as follows: control (+) (wheat flour), control (-) (rice flour), T1 (1,800 rpm, 1 min), T2 (1,800 rpm, 2 min), T3 (1,800 rpm, 3 min), T4 (3,600 rpm, 1 min), T5 (3,600 rpm, 2 min), T6 (3,600 rpm, 3 min). In this study, rice flour was used in the T1 to T6 samples. The pH of the batter tended to be higher when the mixing speed was slower and the time was shorter depending on the ultra-high mixing conditions. The moisture content of T3 was highest, and there was no difference according to the ultra-high speed conditions. The specific volumes of the ultra-high mixing treatments were higher than those of the control samples. The relationship between the specific volume, hardness and springiness of rice bread according to the mixing speed and time was weak. Therefore, it is considered that the application of ultra-high speeds when manufacturing gluten-free batter can have a positive effect on improving the production efficiency by reducing the processing time.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.985-997
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• 2016

The objectives of this study, which filled gaps in previous studies, were: (1) to find the optimal mixing condition of nanoemulsions containing oleoresin capsicum (OC), Tween 80, propylene glycol (PG), and sucrose monostearate (SES) by microfluidization; (2) to investigate their properties and stability depending on such factors as pH, temperature, and heating time; (3) to measure the effect of adding ascorbic acid. In order to test these objectives, the following three experiments were conducted: Firstly, in order to find the optimal mixing ratio, nanoemulsions containing OC - the mean diameter of which is smaller than 100 nm - were prepared through the process of microfluidization; and their mean particle size, zeta potential, and capsaicinoids were measured. The test results indicated that the mixing ratio at OC : Tween 80 : PG + water(1:2) = 1 : 0.2 : 5 was optimal. Secondly, the properties and stability of nanoemulsions were investigated with varying parameters. The test results illustrated that single-layer nanoemulsions and double-layer nanoemulsions coated with alginate were stable, irrespective of all the parameters other than/except for pH 3. Thirdly, the properties of nanoemulsions were then analyzed according to the addition of ascorbic acid. The results demonstrated that the properties of single-layer nanoemulsions were not affected by addition of ascorbic acid. In case of alginate double-layer nanoemulsions, the particle size was reduced, and zeta potential increased with the addition of ascorbic acid. In conclusion, the demonstrated stability of various nanoemulsions under the different conditions in the present study suggests that these findings may constitute a basis in manufacturing various food-grade products which use nanoemulsions-and indicate that food nanoemulsions, if adopted in the food industry, have the potential to satisfy both the functionality and acceptability requirements necessary to produce commercially marketable food-grade products.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.59-65
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• 2024

In this study, in order to improve the mechanical properties and durability of asphalt mixtures, a modifier (CSM, Cationized Silicate Modifier) was applied to asphalt to derive optimal mixing ratio conditions. Design of asphalt mixture using modified asphalt binder was conducted, and moisture resistance and dynamic stability were evaluated for optimal mixing conditions. The evaluation results showed that it exceeded the standards stipulated in the relevant guidelines, and as a result of conducting a water permeability test on the optimal mixing condition, it was confirmed that impermeable performance was secured. As a result of examining the noise reduction performance through field test, a noise reduction performance of about 10 dB was secured compared to before paving. It will be necessary to secure reliability through continuous noise generation evaluation in the future.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.5
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• pp.407-414
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• 2001

In this study, the absorption kinetics of $CO_2$onto a mixture of AMP (2-amino-2-methyl-1-propanol) MEA (monoethanolamine) water were investigated at 30 and 4$0^{\circ}C$ using a packed absorption tower. Solubility and absorption rate of $CO_2$into alkanolamine solutions and optimal condition of $CO_2$absorption process were investigated. The experimental conditions are as follows; temperature of 30 and 4$0^{\circ}C$, gas flow rate of 3ι/min for the absorption tower, and liquid flow rate of 0.1ι/min. Feed gas was a mixture of 85% $N_2$and 15% $CO_2$. The experimental results showed that AMP had greater solubilities and faster absorption rates than MEA and DEA. In addition, MEA had the fastest initial reaction rate. To improve the properties of AMP which have low initial reaction rate and high cost, AMP was used with MEA. The mixing ratio was also changed in constant total molarity of 1,2,3 and 4. The experimental results can be summarized as follows: (1) in solubility experiment, the addition of MEA in constant total polarity decreased the solubility of $CO_2$in AMP/MEA mixture. (2) from 0 to about 0.3 in mixing ratio, the solubility of $CO_2$in AMP/MEA mixture had little differences compared with the sum of solubility of AMP only and solubility of MEA only . (3) mixing ratio of 0.3 was found to be an optimal point with the fastest $CO_2$absorption rate.

• 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.

• Journal of Environmental Science International
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• v.20 no.6
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• pp.767-773
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• 2011

The objectives of this research are to investigate the proper coagulation conditions which are a type and doses of coagulants, mixing conditions (velocity gradients and mixing times), pH and so on through Jar-test, to evaluate the flux variations, permeate, backwashing according to characteristics of pretreatment of the wastewater by means of MF membranes for river maintenance water reuse. The effluent water from B-city K-sewage treatment plant are used for this research. Turbidity and suspended solids(SS) are 14.2 NTU and 10.4 mg/L respectively. This condition causes fouling for membrane process. The flux decline could be reduced when coagulation pretreatment was carried out. Optimal coagulations PAC which are commonly used in the sewage treatment plant was observed in this research. The results indicate that an optimal coagulation dose and pH are 80 ppm and pH of 7 respectively, but coagulation efficiency was lower at strong acid or strong base. Results showed that continuous and steady operations in membrane separation process by means of the effective removal of organic matter and turbidity with coagulation pretreatment of sewage secondary effluent were achieved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5721-5727
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• 2015

Paint must be resistant to the wear and tear of the atmosphere and should maintain its color and finish for a long time. The solvents of paints were organic solvent and water, common artificial source of VOCs(Volatile organic Solvent) include organic solvent. Using of organic solvent paint was decreased in the interior parts of automotive, exterior parts were still used organic solvent paint. Adhesive strength of water-paint was poor to compare with organic solvent paint and peeled off from the base materials, it was big quality problem. In this study, adhesive characteristics of water-paint and silane mixture was investigated. To improve adhesive strength of water-paint, it was necessary to mixing of adhesive material. Adhesive strength was measured using UTM(Universal Test Instrument) by ASTM D1002 and Peeling off condition was by ASTM D3359. Optimal mixing condition of water-paint and silane adhesive were $25^{\circ}C$, 500rpm, 20min., concentration of silane adhesive was 5 wt%.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.97-104
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• 2017

A bentonite mixing with local soil widely used as liner layer for landfill should have low permeability less than $1{\times}10^{-7}cm/s$. But there are several limitations of bentonite used as liner layer, such as drying shrinkage cracking, ineffective waterproof ability under salt water condition like flocculation under sea water. The purpose of this research is the development of a salt resistance bentonite by mixing sepiolite and guar gum to overcome the weak points of bentonite to get high water resistance capacity and permeability coefficient below $1{\times}10^{-7}cm/s$ under salt water condition. After having performed drying shrinkage cracking test, swelling index test, compaction test, and hydraulic conductivity test we confirmed the optimal mixing ratio of materials and evaluated the performance of materials.