• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.420-425
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• 1986

This study was conducted to investigate the influence of air temperature and relative humidity on excessive drying rate of burley tobacco. In experiment I, 4 temperatures and I humidity by day and air curing by night were treated from initial curing stage. In experiment II, 15 combinations of 3 temperatures and 5 humidities were applied from the yellow stage of cure. Yellowish cured leaves resulted from overdrying at high temperature and especially, at low humidity. How- ever, these were not produced at 75-80% RH and under 35$^{\circ}C$ by day with air curing b y night. The proper range of temperature and humidity for desirable color of cured leaf were the combinations of 30$^{\circ}C$, 75-80% RH or 35$^{\circ}C$, 80-85% RH. As excessive drying leaves increased, physical properties of cured leaves were poorer and chemical contents were less decomposed.

• Resources Recycling
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• v.19 no.6
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• pp.43-50
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• 2010

The crisis of energy gives rise to the growing concerns over continuing uncertainty in the energy market. Under these circumstances, there are also increasing interests on coals. In particular, Low Rank Coal (LRC) is receiving gradual attentions from green industry. But due to is high moisture content range from 30 - 60%, drying process has to be preceded before being utilized as power plant. In this study drying kinetics of LRC is induced by using a fixed-bed reactor. The drying kinetics was evaluated in from of the particle size, the inlet gas temperature, the drying time, the gas velocity, and the LID ratio. The consideration of the reynold's number was taken for correction of gas velocity, particle size and LID was taken for correction of reactor diameter, packing height of coal. As being seen as characteristic of drying coal, it can be found that fixed-bed reactor can contributed to active drying of free water. In this sense, it could be considered that phase boundary reaction is appropriate mechanism.

• Journal of the Korean Ceramic Society
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• v.33 no.9
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• pp.1057-1063
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• 1996

Y2O3-CeO2-ZrO2 powders were prepared from water-soluble salts using a coprecipitation method. The forming process of oxide and the characteristics of the calcined powders treated in different drying conditions were investigated. The oxidation was occurred at the temperature of around 40$0^{\circ}C$ and the main crystallization of ZrO2 around $600^{\circ}C$. On calcination at $600^{\circ}C$ heating lamp-dried powders consisted of agglomerates of globular morphology with average agglomerate size of 2.27${\mu}{\textrm}{m}$ and specific surface area of 68.3m2/g and spray dried powders contained dense spheric particles with average agglomerate size of 1.35${\mu}{\textrm}{m}$ and specific surface area of 11.0m2/g which exhibited low agglomeration tendency. Removal of the water by a freeze-drying technique produced calcined powders containing flake-like secondary particle structures with wide agglomerate size distri-bution of 0.1-60${\mu}{\textrm}{m}$ and specific surface area of 24.5${\mu}{\textrm}{m}$. The 20 MPa-pressed density (36.8-41.4% T,D) of calcined powders did not nealy depend on drying methods whilst compaction ratio of calcined powders derived from freeze-drying was the highest ( 6.24) among three drying methods. On continuous heating up to 150$0^{\circ}C$ the sinterability of calcined powders derived from heating lamp-drying was superior to those derived from spray-and freeze-drying. The final sintered density of calcined powders was the highest (96% T,D at 150$0^{\circ}C$) in case of heating lamp-drying.

• Journal of Korean Society of Forest Science
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• v.36 no.1
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• pp.26-32
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• 1977

Press drying was used on sapwood and heartwood of oak (Qercus acutissima Carruthers) to find profitable means of drying low grade logs. This study was designed to investigate the process of press drying considering core temperature, current moisture content, drying rate, drying time, final moisture content, dimensional change and drying defects. The drying tests were conducted using 1.5 centimeter thick material at platen temperature of $175^{\circ}C$ and pressure of 35psi. The results were summarized as fallows. 1. Core temperature was divided into three stages of drying characterized by initial heating period, plateau temperature, and period of rising core temperature. Plateau temperature of heartwood material was higher and longer than that of sapwood material. 2. The predicting equation for change in drying rate of sapwood material was log y=-2.7925-0.0811x as function of time. That of heartwood material was log y=-3.3382-0.0468x. 3. Sapwood material reduced the moisture content from 59 to 2.5 percent in 45minutes. Heartwood material reduced the moisture content from 64 to 3.3 percent in 55 minutes. 4. Shrinkage during press drying were 20.4 percent in thickness direction and 2.5 percent in width direction. Recovery on equilibrium conditioning at 65 percent relative humidity and temperature of $20^{\circ}C$. were 11.4 percent in thickness direction and 49.4 percent in width direction. 5. Heartwood material developed severe honeycombing and moderate checking. The sapwood material dried without honeycombing, checking and collapse. All material kept wood flat.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.225-230
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• 2004

Volatile organic compounds (VOCs) are low calorific value gases (LCVG) emitted from chemical processes such as painting booth, dye works and drying processes etc. Characteristics of VOCs are low calorific values less than 150 kcal/$m^3$, high activation energy for ignition and low energy output. These characteristics usually make combustion unstable and its treatment processes needs high-energy consumption, The cyclone combustion system is suitable for LCVG burning because it can recirculate energy through a high swirling flow to supply the activation energy for ignition, increases energy density to make a combustion temperature higher than usual swirl combustor and also increases mixing intensity, This research was conducted to develop optimized cyclone combustion system for thermal oxidation of VOCs. This research was executed to establish the effect of swirl number with respect to the combustion temperature and composition of exhausted gas in the specific combustor design.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.221-233
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• 2013

This study was performed to identify the effect of end-coating around pith of heavy timbers of Red pine and Korean pine on high temperature and low humidity drying characteristics. Total drying times were 268 hours, and ranges of final moisture content was investigated that Red Pine 9.2% to 10.8% MC for square and round timber, in case of Korean Pine 15.0% to 22.0% MC for square timber, 12.8% to 20.4% MC for round timber. Moisture content distribution of Red Pine was a uniform, but part of high moisture content was found in Korean Pine. In case of Korean pine, the surface checks were occurred more severe than in case of Red pine, and end-coating treatment were investigated to be ineffective on surface check. The internal checks were only formed on the two timbers. The value of the case hardenings was investigated that the ranges 3.7% to 9.1% for Red pine. In case of Korean pine, on the other hand, the case hardenings presence a few as 20.9% to 35.8%.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.387-393
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• 1995

Diffusion coefficients of moisture and solid, reaction rate constants of carotene destruction, and the fitness of drying models for moisture transfer were determined to study the characteristics of mass transfer during osmotic dehydration. Moisture loss and solid gain were increased with increase of temperature and concentration; temperature had higher osmotic effect than concentration. Diffusion coefficient showed similar trend with osmotic effect. Diffusion coefficients of solids were larger than those of moisture because the movement of solid was faster than that of moisture at the high temperature. Reaction rate constants were affected to the greater extent by concentration changes than by temperature changes. Arrhenius equation was applied to determine the effect of temperature on diffusion coefficients and reaction rate constants. Moisture diffusion required high activation energy in $20^{\circ}Brix$, while relatively low in $60^{\circ}Brix$. To predict the diffusion coefficients and reaction rate constants, a model was established by using the optimum functions of temperature and concentration. The model had high $R^2$ value when applied to diffusion coefficients, but low when applied to reaction rate constants. Quadratic drying model was most fittable to express moisture transfer during drying. In conclusion, moisture content of carrots could be predictable during the osmotic dehydration process, and thereby mass transfer characteristics could be determined by predicted moisture content and diffusion coefficient.

• Journal of Life Science
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• v.13 no.1
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• pp.15-20
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• 2003

Seeds treated before sowing should be dried for their quality control on their sale or storage. The experiments were done to clarify the effect of drying, temperature and light quality treated during drying and germination on germination of gourd (Lagenaria siceraria Standl.) seeds. Drying of treated seeds was done at $35^{\circ}C$. After treated seeds were dried. their germination test was done at 10, 20 and $30^{\circ}C$ on the condition of darkness, but with blue, red, far-red light and darkness as light quality treatments. FR-yongjadaemok and FR-kunghap were used as test cultivars and their daily germination rates were measured at treatment levels. Its presowing hydrated seeds were dried 10 hours at $35^{\circ}C$ until reached below their original moisture content, and germination rate between the above dried seeds and the conventional dry-heated ones was not significantly different. At $30^{\circ}C$ germination temperature, the treated seeds showed higher initial germination rate when dried under red light illumination than under darkness although their germination rates were nearly same at each temperature of 10 and $20^{\circ}C$ being relatively low. Effect of the red light treatment during their drying continued to more than 3 months. Germination rate of the red light treated seeds during drying was reduced by far-red light treated during their germination. The initial rate to the second day after sowing were higher under red light and darkness treated during germination than under the two other lights.

• Korean Journal of Medicinal Crop Science
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• v.21 no.5
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• pp.394-400
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• 2013

This study was carried out in order to examine the germination characteristics of Atractylodes japonica seeds, and it was to develop the more efficient pre-treatment and production system of the seeds. Experiment was performed by two ways-temperature control (10, 15, 20, $25^{\circ}C$) and shading treatment (full sunlight, 35, 50, 75, 95% of full sunlight). Seed pre-treatment before the each experiment was carried out by temperature (with low temperature and wetting treatment (LTW) for 0, 15, 30, 45 and 60 days) and shading treatment (with drying at room temperature (DRT), drying at low temperature (DLT) and water soaking (WS) for 48 hours). Seeds of A. japonica were germinated well under temperature control (overall 85.3~100%), especially high temperature. And, the seeds pre-treated with LTW for 45 days germinated with a 100% success rate. Under the surveying shading treatment, the highest germination rate was 95.8% with DRT and overall 63.2~95.8%. Germination rate under seeds with WS was 63.2~7.8%. As a result of surveying the whole experiment, A. japonica seeds don't need to pre-treat cause of high germination, but if it is performed with LTW for a certain period of time, it would be more productive.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.437-444
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• 2010

Dry Process(natural drying, hot-air drying, oil fry drying), optimized mixture ratio and the condition of carbonization was carried out in order to improve the product durability develop eco-friendly solid fuel mixing food waste and paper sludge. As a result of the experiment, oil fry drying process was the fastest method for drying food waste and paper sludge mixture that contains 80% water inside, and the optimized mixture ratio to minimize the generating concentration of chlorine gas against caloric value of mixture ratio was 7:3. Additionally proper temperature of product carbonization was about $200^{\circ}C$ and shown increasing product durability through the carbonization. Therefore, the pelletized solid fuel be shaped diameter around 0.5cm, length 2cm under which was pulverized and molded using 7:3 mixture of food waste, and paper sludge was the eco-friendly solid fuel possible to be industrialized which is consist of chlorine concentration of below 2.0wt% and the lowest caloric value of over 5,000kcal/kg. In conclusion, this developing manufacturing process of the solid fuel can be interpreted to contribute alternative energy development in accordance with low carbon and green growth era.