• Journal of Biosystems Engineering
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• v.4 no.2
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• pp.65-83
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• 1979

Low-temperature drying systems have been extensively used for drying cereal grain such as shelled corn and wheat. Since the 1973 energy crisis, many researches have been conducted to apply solar energy as supplemental heat to natural air drying systems. However, little research on rough rice drying has been done in this area, especially very little in Korea. In designing a solar drying system, quality loss, airflow requirements, temperature rise of drying air, fan power and energy requirements should be throughly studied. The factors affecting solar drying systems are airflow rate, initial moisture content, the amount of heat added to drying air, fan operation method and the weather conditions. The major objectives of this study were to analyze the effects of the performance factors and determine design parameters such as airflow requirements, optimum bed depth, optimum temperature rise of drying air, fan operation method and collector size. Three hourly observations based on the 4-year weather data in Chuncheon area were used to simulate rough rice drying. The results can be summarized as follows: 1. The results of the statistical analysis indicated that the experimental and predicted values of the temperature rise of the air passing through the collector agreed well. 2. Equilibrium moisture content was affected a little by airflow rate, but affected mainly by the amount of heat added, to drying air. Equilibrium moisture content ranged from 12.2 to 13.2 percent wet basis for the continuous fan operation, from 10.4 to 11.7 percent wet basis for the intermittent fan operation respectively, in range of 1. 6 to 5. 9 degrees Centigrade average temperature rise of drying air. 3. Average moisture content when top layer was dried to 15 percent wet basis ranged from 13.1 to 13.9 percent wet basis for the continuous fan operation, from 11.9 to 13.4 percent wet basis for the intermittent fan operation respectively, in the range of 1.6 to 5.9 degrees Centigrade average temperature rise of drying air and 18 to 24 percent wet basis initial moisture content. The results indicated that grain was overdried with the intermittent fan operation in any range of temperature rise of drying air. Therefore, the continuous fan operation is usually more effective than the intermittent fan operation considering the overdrying. 4. For the continuous fan operation, the average temperature rise of drying air may be limited to 2.2 to 3. 3 degrees Centigrade considering safe storage moisture level of 13.5 to 14 perceut wet basis. 5. Required drying time decrease ranged from 40 to 50 percent each time the airflow rate was doubled and from 3.9 to 4.3 percent approximately for each one degrees Centigrade in average temperature rise of drying air regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on required drying time. 6. Required drying time increase ranged from 18 to 30 percent approximately for each 2 percent increase in initial moisture content regardless of the fan operation methods, in the range of 18 to 24 percent moisture. 7. The intermittent fan operation showed about 36 to 42 percent decrease in required drying time as compared with the continuous fan operation. 8. Drymatter loss decrease ranged from 34 to 46 percent each time the airflow rate was doubled and from 2 to 3 percent approximately for each one degrees Centigrade in average temperature rise of drying air, regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on drymatter loss. 9. Drymatter loss increase ranged from 50 to 78 percent approximately for each 2 percent increase in initial moisture content, in the range of 18 to 24 percent moisture. 10. The intermittent fan operation: showed about 40 to 50 percent increase in drymatter loss as compared with the continuous fan operation and the increasing rate was higher at high level of initial moisture and average temperature rise. 11. Year-to-year weather conditions had a little effect on required drying time and drymatter loss. 12. The equations for estimating time required to dry top layer to 16 and 1536 wet basis and drymatter loss were derived as functions of the performance factors. by the least square method. 13. Minimum airflow rates based on 0.5 percent drymatter loss were estimated. Minimum airflow rates for the intermittent fan operation were approximately 1.5 to 1.8 times as much as compared with the continuous fan operation, but a few differences among year-to-year. 14. Required fan horsepower and energy for the intermittent fan operation were 3. 7 and 1. 5 times respectively as much as compared with the continuous fan operation. 15. The continuous fan operation may be more effective than the intermittent fan operation considering overdrying, fan horsepower requirements, and energy use. 16. A method for estimating the required collection area of flat-plate solar collector using average temperature rise and airflow rate was presented.

• Journal of Biosystems Engineering
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• v.4 no.2
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• pp.64-64
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• 1979

Low-temperature drying systems have been extensively used for drying cereal grain such as shelled corn and wheat. Since the 1973 energy crisis, many researches have been conducted to apply solar energy as supplemental heat to natural air drying systems. However, little research on rough rice drying has been done in this area, especially very little in Korea. In designing a solar drying system, quality loss, airflow requirements, temperature rise of drying air, fan power and energy requirements should be throughly studied. The factors affecting solar drying systems are airflow rate, initial moisture content, the amount of heat added to drying air, fan operation method and the weather conditions. The major objectives of this study were to analyze the effects of the performance factors and determine design parameters such as airflow requirements, optimum bed depth, optimum temperature rise of drying air, fan operation method and collector size. Three hourly observations based on the 4-year weather data in Chuncheon area were used to simulate rough rice drying. The results can be summarized as follows: 1. The results of the statistical analysis indicated that the experimental and predicted values of the temperature rise of the air passing through the collector agreed well.2. Equilibrium moisture content was affected a little by airflow rate, but affected mainly by the amount of heat added, to drying air. Equilibrium moisture content ranged from 12.2 to 13.2 percent wet basis for the continuous fan operation, from 10.4 to 11.7 percent wet basis for the intermittent fan operation respectively, in range of 1. 6 to 5. 9 degrees Centigrade average temperature rise of drying air.3. Average moisture content when top layer was dried to 15 percent wet basis ranged from 13.1 to 13.9 percent wet basis for the continuous fan operation, from 11.9 to 13.4 percent wet basis for the intermittent fan operation respectively, in the range of 1.6 to 5.9 degrees Centigrade average temperature rise of drying air and 18 to 24 percent wet basis initial moisture content. The results indicated that grain was overdried with the intermittent fan operation in any range of temperature rise of drying air. Therefore, the continuous fan operation is usually more effective than the intermittent fan operation considering the overdrying.4. For the continuous fan operation, the average temperature rise of drying air may be limited to 2.2 to 3. 3 degrees Centigrade considering safe storage moisture level of 13.5 to 14 perceut wet basis.5. Required drying time decrease ranged from 40 to 50 percent each time the airflow rate was doubled and from 3.9 to 4.3 percent approximately for each one degrees Centigrade in average temperature rise of drying air regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on required drying time.6. Required drying time increase ranged from 18 to 30 percent approximately for each 2 percent increase in initial moisture content regardless of the fan operation methods, in the range of 18 to 24 percent moisture.7. The intermittent fan operation showed about 36 to 42 percent decrease in required drying time as compared with the continuous fan operation.8. Drymatter loss decrease ranged from 34 to 46 percent each time the airflow rate was doubled and from 2 to 3 percent approximately for each one degrees Centigrade in average temperature rise of drying air, regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on drymatter loss. 9. Drymatter loss increase ranged from 50 to 78 percent approximately for each 2 percent increase in initial moisture content, in the range of 18 to 24 percent moisture. 10. The intermittent fan operation: showed about 40 to 50 percent increase in drymatter loss as compared with the continuous fan operation and the increasing rate was higher at high level of initial moisture and average temperature rise.11. Year-to-year weather conditions had a little effect on required drying time and drymatter loss.12. The equations for estimating time required to dry top layer to 16 and 1536 wet basis and drymatter loss were derived as functions of the performance factors. by the least square method.13. Minimum airflow rates based on 0.5 percent drymatter loss were estimated.Minimum airflow rates for the intermittent fan operation were approximately 1.5 to 1.8 times as much as compared with the continuous fan operation, but a few differences among year-to-year.14. Required fan horsepower and energy for the intermittent fan operation were3. 7 and 1. 5 times respectively as much as compared with the continuous fan operation.15. The continuous fan operation may be more effective than the intermittent fan operation considering overdrying, fan horsepower requirements, and energy use.16. A method for estimating the required collection area of flat-plate solar collector using average temperature rise and airflow rate was presented.

• Journal of Power System Engineering
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• v.14 no.4
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• pp.23-28
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• 2010

Of the roughly four million known substances, about 60,000 are processed and sold ; many of these must be dried. Many materials are processed in the liquid state - ideal for mixing and reacting - but most products are needed or wanted as dry, or relatively dry, solids. Usually operation is just below atmospheric pressure, as with direct dryers, but some are built for vacuum operation with pressures as low as 26.66kPa abs.. In spite of the global-class aquiculture agriculture and fisheries technology of our country, the processing technologies are lags behind the other nations relatively. These problems are considered to be caused directly by the lack of drying technologies. This paper is concerned to the experimental results of drying heat transfer characteristics for the green energy type vacuum dryer for the high quality agriculture and fisheries production.

• Journal of Sericultural and Entomological Science
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• v.13 no.2
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• pp.155-160
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• 1971

This experiment was carried out to investigate the cocoon reeling condiditions required to technical balance work on the automatic silk reeling machine. The results obtained were as follows. 1) Reasonable reeling velocity with regard to raw silk yield and to reeling efficiency varied according to cocoon reelability. It was observed to be about 150m/min on good reelability cocoon (850m of nonbreaking bave length), about 120m/min on medium reelability cocoon (650m of nonbreaking bave length) and from 90m/min to 120m/min on bad reelability cocoon (500m of nonbreaking bave length) 2) Low temperature drying of cocoon (T$_3$) improved the reelability of cocoon, but increased the reeling accidance with deteriorating the quality of raw silk more than the control(T$_1$) or high temperature drying of cocoon (T$_2$). No significant difference was observed in its raw silk yield and silk by-product with regard to cocoon drying temperature. 3) Incomplete drying of cocoon (T$_3$) improved the reelability of cocoon, but increased the reeling accidance with deteriorating the quality of raw silk more than the control(T$_1$) or over drying of cocoon(T$_2$). No significant difference was observed in its raw silk yield and silk by-product with regard to cocoon drying degree. It was cocoon drying condition of cocoon was the control(T$_1$) or high temperature(T$_2$) rather than low temperature (T$_3$) in cocoon drying process. Control (T$_1$) or over drying of cocoon (T$_2$) was adequate rather than incomplete drying of cocoon (T$_3$) for the improvement of the quality of raw silk on the automatic silk reeling process. 4) It was found that the reasonable cooking condition of cocoon was optimum cooking with 4$0^{\circ}C$ of reeling temperature or incomplete cooking with 45$^{\circ}C$ of the reeling temperature in the automatic silk reeling of the domestic cocoon.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1994.06f
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• pp.139-160
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• 1994

The-state-of-the-art of rice drying in the U.S.A. is presented. The U.S.A. is a minor producer but major exporter of rice. Head yield is its major criterion in evaluating rice quality . A decrease of 1 to 3 points in head yield can be expected to occur in a well-designed rice-drying system. Rice is dried on the farm in bins in the U.S. A., and n high-temperature continuous -flow dryers at the elevator level. Two relatively new rice-drying systems are discussed in some detail. : The top-bin/in -bin-counterflow bin-type on-farm dryer, and the concurrent-flow high-temperature elevator dryer.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.19-29
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• 2006

Drying is the least developed of all unit operations of paper and board manufacture. While groundbreaking developments were Introduced during the several past decades in forming, pressing and calendering, no radical changes occurred in drying. The cylinder-drying technology is now more than 200 years old and, while it was subject to many incremental improvements, many of its inherent problems persist. We believe that conventional drying is now approaching the end of its life and the industry is ready for a major breakthrough in drying. Indeed several innovative technologies already exist at various stages of development or commercialization. In general, the novel drying technologies are striving to increase the drying rate, improve the product quality and boost the energy efficiency of drying. A novel, drying method, $Papridry^{TM}$, which combines conductive and convective heat transfer to obtain very high drying rates, is at an advanced stage of development at Paprican. The results obtained when drying printing paper ana board on a self-standing pilot $Papridry^{TM}$ machine and on the pilot paper machine equipped with a tandem of two $Papridry^{TM}$ units demonstrate both, the high drying rate and improved product quality achieved by using this drying method. A mathematical model of this operation has been developed and the software compiled with this model was used to calculate the effect of installing a $Papridry^{TM}$ unit into an existing dryer section. The model also allows to calculate the z-direction distribution of moisture and temperature at various points of the dryer section.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.439-446
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• 2015

Kimbugak is one of Korea's traditional snacks made of laver. This study was conducted to investigate the physical drying and frying characteristics of kimbugaks made by a pasting & garnishing machine. The drying and frying characteristics should be analyzed to develop a continuous operation system for manufacturing kimbugak because kimbugak has a high moisture content after pasting process. Materials for pasting and garnishing on laver were rice gruel and sesame. The aluminum shelf with square hole was selected as a drying shelf. The recommended size of the square hole type was $1.5mm{\times}1.5mm$ because characteristics of deformation and easy separation from the shelf were excellent at the hole size. The drying time of 2 hours was also recommended with the drying temperature of $70^{\circ}C$ based on the test results such as dried condition (good), moisture conten t (3.7%), deformation (12.1 mm), and shrinkage rate (19.8%). As the frying conditions for dried kimbugaks, recommended oil temperature and frying time were $170^{\circ}C$, 15 seconds, respectively when corn oil was used. In the case of frying for undried kimbugaks, recommended oil temperature and frying time were $210^{\circ}C$, 2 - 3 minutes, respectively for improvement of work efficiency.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.213-220
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• 2018

In order to use Pitch pine (Pinus rigida Miller) as the material of the structural glued laminated timber, the effect of the amount of resin exudation due to storage time after the planning and the knot of the lamina were evaluated on the bonding properties of the glued board with resorcinol resin. For Pitch pine that was dried at high temperature ($120{\sim}95^{\circ}C$) and low temperature ($65{\sim}50^{\circ}C$), the flat sawn(tangential section) showed higher amount of resin exudation than the quarter sawn(radial section). And the low temperature drying wood showed higher resin exudation than the high temperature drying wood. The low and high temperature drying wood showed the highest amount of resin exudation on the 3rd day and 7th day, respectively and they were gradually decreased. However, there were no significant differences from 15 to 90 days. Adhesion performances were low until 2~3 days with high exudation of resin, but there were no significant differences after 15 days. Both high temperature and low temperature drying woods satisfied the Korean standard regardless of the storage time. The adhesive strengths of the laminating parts including knots were higher than those of KS criteria, but the wood failures were not satisfied the KS standard. Adhesive performances according to the laminating combinations (quarter sawn + quarter sawn, flat sawn + flat sawn, quarter sawn + flat sawn) were better than those of KS criteria in all laminating combinations in both high temperature and low temperature drying woods.

• Food Science of Animal Resources
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• v.35 no.5
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• pp.597-603
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• 2015

The purpose of this study was to investigate the influence of processing conditions (temperature and time) and binding agent types (glutinous rice flour, potato starch, bean flour, and acorn flour) on the physicochemical and sensory characteristics of ground dried-pork meat product. For this purpose, ground dried-pork meat product was produced by adding several binding agents at different drying temperatures and times. The drying time affected moisture content and water activity in all drying temperature. However, under the similar drying conditions, the extent of drying varied depending on the type of binding agents. The results of sensory evaluation for texture degree and overall acceptability indicated the following: overall, higher drying temperatures and longer drying time heightened the degree of texture, and the overall acceptability varied depending on binding agent type. Physicochemical and sensory characteristics were analyzed to determine any possible correlation. The results revealed a high correlation between moisture content, water activity, shear forces, and sensory evaluation (p<0.01). However, there was no correlation with respect to overall acceptability.

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.425-429
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• 1989

Functional relationships of carotenoid destruction and nonenzymatic browning during red pepper drying were established by the dynamic test using the moisture-temperature-quality history curve in actual drying experiments. The dependence of the rate constants on temperature and moisture content was established and analysed assuming that carotenoid destruction and nonenzymatic browning are the first order and the zero order reaction, respectively. Carotenoid destruction rate constant was high at high moisture and high temperature, and had a minimum value at some intermediate moisture content. As dependence of rate constant on temperature, activation energy of carotenoid decolorization ranged from 7.7 to 27.4 kcal/mol, showing higher value at higher moisture content. Nonenzymatic browning showed higher rate at higher temperature and higher moisture content. Activation energy of browning was in the range of 7.5-20.2 kcal/mol with higher value at higher moisture level.