• Title/Summary/Keyword: Optimum Design Variable

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Prediction of Optimal Extraction Conditions in Microwave-Assisted Process for Antioxidant-Related Components from Thymus quinquecostatus (Microwave-Assisted Process에 의한 섬백리향의 항산화 관련 성분의 최적 추출조건 예측)

  • Kwon Young-ju;Noh Jung-eun;Lee Jung-eun;Lee Sung-Ho;Choi Yong-Hee;Kwon Joong-Ho
    • Food Science and Preservation
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    • v.12 no.4
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    • pp.344-349
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    • 2005
  • Microwave-assisted process (MAP) was applied to extract antioxidant-related components from Thymus quinquecostatus var. japonica Hara. Microwave power(2,450 MHz, $0{\sim}160$ W) and extraction time($1{\sim}5\;min$) were used as independent variables($X_i$) for central composite design to yield 10 different extraction conditions. Response surface methodology was applied to predict optimum extraction conditions for dependent variables of extracts, such as total yield, total phenolics, flavonoid, and electron donation ability depending on different powers and extraction times of MAP. Determination coefficients($R^2$) of regression equations for dependent variables were higher than 0.93 excluding that of total phenolics, and microwave power was predicted more influential than extraction time in MAP (p<0.05). The optimal extraction time for each dependent variable was ranged from 3.36 to 4.97 min, but microwave power showed wide ranges depending on variables. The superimposed contour maps for maximized dependent variables illustrated extraction conditions of 64 to 100 W in microwave power and 2.9 to 4.0 min in extraction time.

Preparation of Cosmeceuticals Containing Wheat Sprout Extracts: Optimization of Emulsion Stability Using CCD-RSM (밀싹 추출물이 함유된 Cosmeceuticals의 제조: CCD-RSM을 이용한 유화안정성 최적화)

  • Jang, Hyun Sik;Ma, Xixiang;Lee, Seung Bum
    • Applied Chemistry for Engineering
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    • v.32 no.3
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    • pp.320-325
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    • 2021
  • In this study, an optimization for the production of water emulsion was designed by adding an extract of wheat sprout, which is known to contain a large amount of antioxidants. The central composite design of reaction surface analysis method (CCD-RSM) was used for the optimization process. The amount of emulsifier, emulsification time, and added amount of wheat sprout extract were selected as independent variables based on our preliminary experiments. The mean droplet size (MDS), viscosity, and emulsion stability index (ESI) were set as the responses to evaluate the stability of the emulsion. For each independent variable, the P-value and coefficient of determination were evaluated to verify the reliability of the experiments. From the result of CCD-RSM, optimum conditions for the emulsification were determined as 23.6 min, 7.7 wt.%, and 3.9 wt.% for the emulsification time, amount of emulsifier, and amount of sprout, respectively. From the optimized condition obtained, MDS, viscosity, and ESI after 7 days from reaction were estimated as 252.3 nm, 616.7 cP, and 88.7%, respectively. The overall satisfaction was 0.9137, which supported the validity of the experiments, and the error rate was measured at 0.5% or less by advancing the experiments. Therefore, an optimized process for producing an emulsion by adding the malt extract was designed by the CCD-RSM.

Design and Fabrication of Sputter Coating System for Ophthalmic Lens (안경렌즈코팅용 소형 Sputter Coating System 설계 및 제작에 관한 연구)

  • Park, Moonchan;Jung, Boo Young;Kim, Eung Sun;Lee, Jong Geun;Joo, Kyung Bok;Moon, Hee Sung
    • Journal of Korean Ophthalmic Optics Society
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    • v.13 no.1
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    • pp.53-58
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    • 2008
  • Purpose: To design and fabricate the small sputter coating system for the Ophthalmic lens. Methods: The design of sputter target was done using macleod program for AR coating and mirror coating of Ophthalmic lens with Si target and then the sputter system was fabricated. Results: The optimum condition of AR coating with Si target was [air|$SiO_2$(81.3)|$Si_3N_4$ (102)|$SiO_2$(19.21)|$Si_3N_4$(15.95)|$SiO_2$(102)|glass], for blue color mirror coating [air|$SiO_2$(56.61)|$Si_3N_4$(135.86)|$SiO_2$(67.64)|$Si_3N_4$(55.4)|$SiO_2$(53.53)|$Si_3N_4$(51.28)|glass], for green color coating [air|$SiO_2$(66.2)|$Si_3N_4$(22.76)|$SiO_2$(56.58)|$Si_3N_4$(140.35)|$SiO_2$(152.35)|$Si_3N_4$(70.16)|$SiO_2$(121.87)|glass], for gold color [air|$SiO_2$(83.59)|$Si_3N_4$(144.86)|$SiO_2$(11.82)|$Si_3N_4$(129.93)|$SiO_2$(90.01)|$Si_3N_4$(88.37)|glass]. Conclusions: In the fabrication of sputtering coating apparatus, Dual cathode with same Ti target were coated at the same time on both sides of Ophthalmic lens to lessen the time of coating on Ophthalmic Lens and save the cost of the lens. The distance of target-substrate of cathode was variable from 12.5 cm to 20 cm. Turbo pump was used to take the whole coating process about 15 min. instead of diffusion pump. The lens holder was made to coat 2 pairs lens every coating and was rotated to get the uniformity of thin film.

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A Feasibility Study on the Use of Liner and Cover Materials Using Sewage Sludge (하수슬러지의 차수재 및 복토재로의 이용타당성에 관한 연구)

  • 유남재;김영길;박병수;정하익
    • Journal of the Korean Geotechnical Society
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    • v.15 no.2
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    • pp.43-71
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    • 1999
  • This research is an experimental work of developing a construction material using municipal wastewater sludge as liner and cover materials for waste disposal landfill. Weathered granite soil and flyash, produced as a by-product in the power plant, were used as the primary additives to improve geotechnical engineering properties of sludge. For secondary additives, bentonite and cement were mixed with sludge to decrease the permeability and to increase the shear strength, respectively. Various laboratory test required to evaluate the design criteria for liner and cover materials, were carried out by changing the mixing ratio of sludge with the additives. Basic soil properties such as specific gravity, grain size distribution, liquid and plastic limits were measured to analyze their effects on permeability, compaction, compressibility and shear strength properties of mixtures. Laboratory compaction tests were conducted to find the maximum dry densities and the optimum moisture contents of mixtures, and their effectiveness of compaction in field was consequently evaluated. Permeability tests of variable heads with compacted samples, and the stress-controlled consolidation tests with measuring permeabilities of samples during consolidation process were performed to obtain permeability, and to find the compressibility as well as consolidational coefficients of mixtures, respectively. To evaluate the long term stability of sludges, creep tests were also conducted in parallel with permeability tests of variable heads. On the other hand, for the compacted sludge decomposed for a month, permeability tests were carried out to investigate the effect of decomposition of organic matters in sludges on its permeability. Direct shear tests were performed to evaluate the shear strength parameters of mixed sludge with weathered granite, flyash and bentonite. For the mixture of sludge with cement, unconfined compression tests were carried out to find their strength with varying mixing ratio and curing time. On the other hand, CBR tests for compacted specimen were also conducted to evaluate the trafficability of mixtures. Various test results with mixtures were assessed to evaluate whether their properties meet the requirements as liner and cover materials in waste disposal landfill.

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Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Optimization of Microwave-Assisted Process for Extraction of Effective Components from Mosla dinthera M. (마이크로파 추출공정에 의한 쥐깨풀 유용성분의 추출조건 최적화)

  • Lee Eun-Jin;Kwon Young-Ju;Noh Jung-Eun;Lee Jeong-Eun;Lee Sung-Ho;Kim Jae-Keun;Kim Kwang-Soo;Choi Yong-Hee;Kwon Joong-Ho
    • Food Science and Preservation
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    • v.12 no.6
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    • pp.617-623
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    • 2005
  • Response surface methodology (RSM) was applied to microwave-assisted process (MAP) extraction for effective components from Mosla dianthera M. Microwave power (2,450 MHz, 0-160 W) and extraction time (1-5 min) were used as independent variables ($X_i$) for central composite design to yield 10 different extraction conditions. Optimum conditions were predicted for dependent variables of $75\%$ ethanol extracts, such as total yield($Y_1$), total phenolics($Y_2$), total flavonoids($Y_3$), and electron donation ability($Y_4$, EDA). Determination coefficients ($R^2$) of regression equations for dependent variables ranged from 0.8397 to 0.9801, and microwave power was observed to be more influential than extraction time in MAP. The maximal values of each dependent variable predicted at different extraction conditions of microwave power (W) and extraction time (min) were as follows; $6.76\%$ of total yield at 142.00 W and 4.36 min, 78.68 mg/g of total phenolics at 136.78 W and 4.40 min, 6.75 mg/g of total flavonoids at 159,69 W and 3.17 min, and $49.81\%$ of EDA at 133.87 W and 4.47 min, respectively. The superimposed contour maps for maximizing dependent variables illustrated the MAP conditions of 79 to 113 W in power and of 2.73 to 3.84 min in extraction time.

Improvement of Heat Pump Heating Performance by Selective Heat Storage Using Air Heat of Inside and Outside Greenhouse (온실 내외부 공기열의 선택적 축열에 의한 히트펌프 난방성능 개선)

  • Kwon, Jin Kyung;Kim, Seung Hee;Jeon, Jong Gil;Kang, Youn Koo;Jang, Kab Yeol
    • Journal of Bio-Environment Control
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    • v.26 no.4
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    • pp.353-360
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    • 2017
  • In this study, the design and performance test of the air to water heat pump capable of producing hot water for greenhouse heating by using the surplus solar heat inside the greenhouse and the air heat outside greenhouse as the selective heat source were conducted. The heat storage operations using the surplus solar heat and the outside air heat were designed to be switched according to the setting temperature of the greenhouse in consideration of the optimum temperature range of the crop. In the developed system, it was possible to automatically control the switching of heat storage operation, heating and ventilation by setting 12 reference temperatures on the control panel. In the selective heat storage operation with the surplus solar heat and outside air heat, the temperature of thermal storage tank was controlled variably from $35^{\circ}C$ to $52^{\circ}C$ according to the heat storage rate and heating load. The heat storage operation times using the surplus solar heat and outside air heat were 23.1% and 30.7% of the experimental time respectively and the heat pump pause time was 46.2%. COP(coefficient of performance) of the heat pump of the heat storage operation using the surplus solar heat and outside air heat were 3.83 and 2.77 respectively and was 3.24 for whole selective heat storage operation. For the comparative experiment, the heat storage operation using the outside air heat only was performed under the condition that the temperature of the thermal storage tank was controlled constantly from 50 to $52^{\circ}C$, and COP was analyzed to be 2.33. As a result, it was confirmed that the COP of the heat storage operation using the surplus solar heat and outside air heat as selective heat source and the variable temperature control of the thermal storage tank was 39% higher than that of the general heat storage operation using the outside air heat only and the constant temperature control of the thermal storage tank.

Effects of Optimized Co-treatment Conditions with Ultrasound and Low-temperature Blanching Using the Response Surface Methodology on the Browning and Quality of Fresh-cut Lettuce (반응표면분석법으로 최적화한 초음파와 저온 블랜칭의 병용처리 조건이 신선편이 양상추의 갈변과 품질에 미치는 영향)

  • Kim, Do-Hee;Kim, Su-Min;Kim, Han-Bit;Moon, Kwang-Deog
    • Food Science and Preservation
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    • v.19 no.4
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    • pp.470-476
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    • 2012
  • Enzymatic action and microbial growth degrade the quality of fresh-cut lettuce. Browning, a bad smell, and softening during storage are the major forms of quality deterioration. Health-oriented consumers tend to avoid foods treated with chemicals to maintain their freshness. This study was conducted to evaluate the change in the quality of fresh-cut lettuce with combined low-temperature blanching (LB) and ultrasonication (US). The optimum condition was selected using the response surface methodology (RSM), through a regression analysis with the following independent variables; the ultrasonication time (X1), blanching temperature (X2), blanching time (X3), and dependent variable; ${\Delta}E$ value (y). It was found that the condition with the lowest ${\Delta}E$ value occurred with combined 90s US and $45^{\circ}C$ 90s LB (US+LB). The combined treatment group (US+LB) was stored at $10^{\circ}C$ for 9 days with the control group and each single-treatment group, with low-temperature blanching and ultrasonication. Overall, the US+LB group had a significantly high $L^*$ value, which indicates significantly low $a^*$, $b^*$, ${\Delta}E$, browning index, PPO, and POD activity values, and a low total bacteria count (p < 0.05). The US+LB group also had the highest sensory score (except for aroma and texture; p > 0.05).