• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.370-377
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• 2000

The red ginseng is very popular as a health food. It has been manufactured with raw ginseng by the conventional method. But, the yield of the heaven grade ginseng (the best quality red ginseng) among the whole products is around 5-7％, Therefore, the yield should be improved in order to increase economic returns. In this study, a new model of drying system was developed to improve the yield of heaven grade ginseng from 7% to 15% or more. For this system, temperature and relative humidity were controlled by the feedback control system, and a solenoid valve for steam supply and other variables were controlled by the PC. The special features of this system developed are an image processing system for monitoring the red ginseng during the drying process in the drying chamber, and a cylindrical porous tray for holding ginseng that is rotating with the speed of 0-10rpm in the drying chamber and makes uniform drying of red ginseng possible.

• Journal of Biosystems Engineering
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• 제11권1호
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• pp.52-63
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• 1986

This study was performed to find out drying characteristics and develop drying model for the design of an efficient dryer or drying system of red peper. The basic model which describes drying phenomenon of red pepper was firstly established, and drying tests were conducted at 14-different drying conditions. In this test, the effects of drying air temperature and relative humidity on the rate of drying were undertaken. Finally, a new drying model based on these experimental results was developed to describe the drying characteristics of red pepper. The results from this study may be summarized as follows. 1. Drying constant of the basic model established from Lewis' experimental model and diffusion equation was theoretically deduced as a function of moisture content and inner-temperature of red pepper. 2. From the results of drying tests, drying air temperature was found to have the greatest effect on the rate of drying. However, the effect of temperature was small for the condition of high relative humidity, and for low temperature, the effect of relative humidity was found to be large even though the range of relative humidity was low. 3. Modified Henderson equation was found to be better than Chung equation as the EMC model for the estimation of the equilibrium moisture content of red Pepper. 4. Constant-rate drying period did not exist in the red pepper drying test. And falling-rate drying period was divided into three distinct phases. Drying rate was dependent on the moisture content, the inner-temperature of red pepper and the change of physical property due to drying. 5. Drying constant increased with decrease of free moisture content, but it decreased at the end of the drying period. Also, drying constant was dependent on the drying air temperature and relative humidity. 6. The new drying model developed in this study was found to be most suitable in describing the drying characteristics of red pepper. Therefore, it may be concluded that drying time could be accurately estimated by the new drying model.

• Journal of Biosystems Engineering
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• 제21권1호
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• pp.72-83
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• 1996

This study was performed to find out drying characteristics and develop drying model for the design of an efficient dryer or drying system of garlic. The basic model which describes drying phenomenon of garlic was first established. A series of drying test were conducted with two varieties of garlic(Uiseong, Namdo) at 9-different drying conditions (drying temperatures ; $40^{\circ}C$, $50^{\circ}C$, $60^{\circ}C$, relative humidities ; 20%, 35%, 50%) and statistical analysis was made to fit the data with exponential equation, approximated diffusion equation, page equation, thompson equation and wang equation, respectively. In this test, the effects of drying air temperature and relative humidity on the drying rate were undertaken. Finally, new drying model based on these experimental results was developed to describe the drying characteristics of garlic. Also, the volatile components of garlic extracts were investigated. For experiment both Uisoeng and Namdo garlic were dried by heated-air-drying, followed by ether extraction. The extracts were analysed by Gas chromatography/Mass spectrometer.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2001년도 하계 학술대회 논문집
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• pp.226-231
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• 2001

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 동계 학술대회 논문집
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• pp.389-394
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• 2000

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.101-110
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• 2014

Purpose: The purpose of this study is to develop a system to optimize drying potential energy of the exhausted hot air by changing relative humidity of the air. This study modified the conventional drying method into a drying method changing exhaust cycle and time in order to control the relative humidity of the exhausted hot air during drying process. Method: A valve on the vent was controlled according to a preset time to change the exhaust cycle and time. This study analyzed the influence of the two different types of drying method on the drying characteristics, required energy, and quality of the dried peppers: conventional drying method exhausting hot air continuously and new drying method controlling exhaust cycle and time. Results: Drying characteristics based on exhaust time showed that drying time increased with exhaust time, and specific energy consumption was reduced by 28% from 18.39 MJ/kg (conventional method) to 13.24 MJ/kg when exhaust time was set to one minute. Drying characteristics based on heating time showed that drying time increased with heating time and specific energy consumption was reduced by 30% from 18.39 MJ/kg (conventional method) to 12.87 MJ/kg when exhaust time was set to 22 minutes. Drying characteristics based on exhaust cycle showed that drying time increased with exhaust cycle, and specific energy consumption was reduced by 31% from 18.39 MJ/kg (conventional method) to 12.69 MJ/kg when exhaust time was set to one minute and exhaust cycle was set to 22 minutes before drying and 40 minutes after drying. The quality of the dried red peppers showed that capsaicin, color, and sugar content were high as 34.87 mg/100g, 66.33, and 11.87%, respectively, when exhaust time was set to one minute and exhaust cycle was set to 22 minutes before drying and 40 minutes after drying. Conclusions: In order to utilize the drying potential energy of the exhausted air during drying process, the conventional drying method was modified into the drying method controlling exhaust cycle and time. The results showed that drying with exhaust cycle of one minute was more efficient in terms of drying time, required energy, and quality of the dried peppers than the one with exhaust cycle of 20~40 minutes.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1473-1479
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• 2009

본 연구는 저비용 고효율의 일체형 곡물 건조/저장 시스템 개발을 위하여 추진되었다. 저장시스템의 용량과 규격, 배출기구의 설치 조건 및 공전, 자전 등의 운전 조건 그리고 대상 곡물의 비중 등의 다양한 조건에서 정해진 배출속도를 충족시키며 곡물의 선입-선출이 보장되는 균일하강 배출기구를 설계하고자 하였다. 곡물 배출 과정에 대한 육안 관찰이 가능한 장치를 제작하여 기존의 균일 단면형 배출기구에서의 곡물의 배출 거동을 관찰하여 기존 기구의 제한점을 검토하였다. 수학적 해석을 통해 주어진 배출 속도를 비롯한 다양한 조건과 곡물의 균일 하강의 조건을 만족시키는 가변 단면형 배출기구의 단면형상을 설계할 수 있는 일반화된 공식을 유도하였으며, 이를 적용하여 제작된 시작품의 운전을 통해 계산값과의 비교 검증의 연구 과정을 수행하였다. 이를 통해 주어진 다양한 조건을 만족하는 나선형의 가변 단면형 균일하강 배출기구의 단면 형상 설계를 위한 일반화된 수학적 모델을 개발하였다.

• Bulletin of the Korean Chemical Society
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• 제18권12호
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• pp.1269-1273
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• 1997

The system which employs iron, palladium, molecular oxygen and hydrogen as a model mono-oxygenase, has been investigated to develop a new method for selective cyclohexane oxidation uner mild conditions. This system provides much higher yield and selectivity for the formation of cyclohexanol and cyclohexanone compared to that of the existing industrial method. When the catalytic system, FeCl2-Pd/alumina, was employed, the oxidation system required acetone as a solvent to be efficient and acidifying the solvent by a little addition of acetic acid or HCl made the system more efficient. The Pd catalyst was recyclable without a significant deactivation but the recycling of ferrous chloride showed the decrease in the activity. On the other hand, the heterogeneous catalytic system, Pd/Fe2O3 could be recovered easily and reused after drying treatment.

• 공학논문집
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• 제4권1호
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• pp.109-118
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• 2002

본 연구에서는 Na-Mont와 알킬 사슬 말단에 산기를 함유하는 베타인 화합물 $R_{11}SO_4$사이의 양이온 교환반응을 이산화탄소를 함유한 증류수를 사용하는 일반 조건 및 이산화탄소가 제거된 증류수를 이용한 상이한 pH 조건 하에서 수행하고, 그 거동을 살펴보았다. 결과적으로 일반 조건 하에서의 교환반응은 49 시간 후에 완전히 종료되었으며, 교환용액 하에 및 메탄올로 세척한 후와 고진공 하에서 건조한 후의 층간거리로는 $23.6\AA$ 및 17.1과 $15.0\AA$이 각각 얻어졌다. 상이한 pH 값 하에서의 교환반응 후에 pH 값 하에서의 교환반응 후에 pH 교환용액 하에서 얻은 층간거리 값은 pH 값에 상관없이 약 24.7과 $25.6\AA$ 사이에 놓였으며, 시료를 공기 및 고진공 하에서 건조한 후의 층간거리로는 약 $20.0\AA$ 및 13.8~14.4 사이의 값이 각각 얻어졌다.

• 지질공학
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• 제20권3호
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• pp.281-295
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• 2010

새롭게 구축된 자동 흙-함수특성곡선 시험장치는 측정원리가 간단하고 연속적인 측정이 가능하며, 시험자에 의해 발생될 수 있는 오차를 최소화하여 보다 정확한 불포화토의 흙-함수특성곡선을 산정할 수 있다. 본 시험장치는 압력조절장치, 플로우셀, 물저장소, 공기방울트랩, 저울, 시료준비장치, 측정시스템 등으로 구성되어 있다. 공기의 압력은 0-300 kPa범위까지 적용할 수 있으며, 단기간내 시험을 완료할 수 있다. 본 시험장치에서는 건조과정과 습윤과정을 재현할 수 있으며, 측정 자동화 프로그램(SWRC)을 이용하여 건조과정과 습윤과정에 따른 시료내 함수비 변화를 실시간으로 확인할 수 있다. 본 시험기를 이용하여 상대밀도 75%인 주문진 표준사에 대한 건조 및 습윤과정의 체적함수비에 따른 모관흡수력을 측정하였다. 측정결과, 건조 및 습윤과정을 거치는 동안 동일한 체적함수비에서 대한 모관흡수력 값이 다르게 나타나는 이력현상(hysteresis)이 발생하였다. 측정된 결과를 토대로 기존의 Brooks and Corey, van Genuchten 및 Fredlund and Xing 방법을 이용하여 흙-함수특성곡선을 예측하였다. 결정계수를 이용하여 이들 방법에 대한 정확성을 평가한 결과 대상토질조건의 경우 van Genuchten방법이 신뢰성이 가장 높은 것으로 나타났다.