• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.381-387
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• 1985

Development and maturation of wheat were studied with reference to the quality of grain and milling properties. 1000-kernel weight and test weight increased as the wheat matured and as the orginal moisture decreased. The time of maturity was estimated 40 days after heading. Moisture content of wheat grain had a correlation coefficient of -0.877＊＊ with 1000-kernel weight, of -0.761＊＊ with test weight, and of 0.915＊＊ with pearling index. The milling data suggest that even in the early stages of maturing, the endosperm represented at large proportion of the grain. However, milling score was relatively constant at about 40 days. Break-Reduction flour ratio was a great difference between wheat varieties. 1000-kernel weight had a high significant correlation of +0.603＊＊ with milling yield, of -0.958＊＊ with ash content, and of +0.956＊＊ with milling score.

• Journal of Biosystems Engineering
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• v.10 no.2
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• pp.36-46
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• 1985

This study was intended to develop the mathematical model of the head-fed type threshing unit. As the first step, the physical model of the threshing phenomena was considered to consist of four separate processes as 1) detachment process of grains, 2) movement of grains between the cylinder and concave, 3) grain penetration through stems of bundle, and 4) grain passing through concave. The mathematical and computer models were developed based on the physical models. Threshing experiments were performed and determined the distribution of grain accumulation along the cylinder shaft by varying the moisture content of grains, feeding rate, and cylinder speed. It was found that the model developed coincided very well with the experimental results for the varied operational conditions. Greater concentration of grains passing through concave toward the thresher inlet was equally true for the model and experiment work for the threshing of grains with higher moisture content and with higher cylinder-speed. The model could be used for obtaining the optimized design or for optimizing the performance of the head-fed type threshing unit if term as to power requirement for threshing may be additionally included in the developed model.

• Journal of Biosystems Engineering
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• v.23 no.5
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• pp.465-472
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• 1998

In this study short gain rough rice(Chu-cheong) with initial moisture content of around 12%(w.b.) was exposed to 3 levels of relative humidity(70, 80 and 90%) and 3 levels of temperature(20, 25 and 3$0^{\circ}C$) of the air, in order to evaluate the adsorption characteristics of rough rice and the rate of cracked kernels which will serve as the basic data when developing the quality adjusting equipment. The result showed that the moisture content of rough rice increased rapidly during the early stages of moisture adsorption like other grains, and at least 70% of the adsorption occurred within the first 24 hours of exposure to the humid environment. Adsorption rate was more related to relative humidity than the temperature of air stream, and the higher the relative humidity, the higher the adsorption rate. And the Page's equation predicted best the adsorption process of this study. Experimental results for the crack generation during the adsorption process showed that the higher the relative humidity the more the cracked kernels, and that the temperature had little effect. An empirical equation was developed to predict the crack ratio for the conditions of this study, and Nishiyama model predicted better the crack generation than Hoerl model.

• Korean journal of applied entomology
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• v.1
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• pp.20-25
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• 1962

A. The increases moisture contents of grain at R.H $75\%,\; and\; 28^{\circ}C$ 1) The moisture contents of polished rice were $0.4\%,\; 1 \%,\; 3.3\%$ higher than control after 4weeks in which had been infested with 100, 200, 500 individuals of weevil at the beginning. respectively. 2) The greatest moisture contents of polished rice was $16.26\%$ for 500 individual infested grain and the lowest one was $14.86\%$ for the 100 individual weevil infested grain after 4 weeks. 3) The increases in moisture contents of grain were proportionally greater with the size of the weevil population. B. Changes in moisture contents of polished rice at the three levels of cylinder which contain 3kgs of grain and 1000 weevils were infested at the beginning of the experiment. 1) The moisture contents of the grain at all the levels of the cylinder which was not infested with weevil, were consistantly decreased in 12 weeks. 2) The moisture contents of the grain at all the levels of the cylenders which had been infested with 1000 weevils at the beginning of the experiment, were increased except top lovel, that were $15.6\%$ for middle, $41.55\%$ for the bottom levels after 12 weeks. 3) The moisture contents of the grain were greater toward bottom in both weevil infested grain and in control. 4) The moisture content increase might be caused by the respiration of the weevils and deterioration of the grain by microorganisms. 5) There were no tendency to confine the weevils at any definite levels, but as the deterioration of the grain goes on, the weevil moved to top levels of cylinders. 5) The decreases in moisture contents of the grain at the top levels of the cylinders might be caused by diffusion of water to the environment. 7) The differences in temperature at three levels of the cylinder from enviroment were little or negative in control but were greater and positive. and the bottom were higher than top in experimental cylinders. 8) The increases of temperature might be caused by the respiration of the weevil and microorganisms.

• Journal of Biosystems Engineering
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• v.27 no.1
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• pp.45-50
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• 2002

This study was performed to develop thin layer drying equations fur short grain rough rice using far-infrared ray. Thin layer drying tests was conducted at four far-infrared ray temperature levels of 30, 40, 50, 60$^{\circ}C$ and two initial moisture content levels of 20.7, 26.2%(w.b.). The measured moisture ratios were fitted to Lewis and Page drying models by stepwise multiple regression analysis. Half response time of drying was affected by both drying temperature and initial moisture content at drying temperature of below 40$^{\circ}C$, but at above 40$^{\circ}C$ was mainly affected by drying temperature. Experimental constant(k) in Lewis model was a function of drying temperature, but K and N in Page model were function of drying temperature and initial moisture content. Moisture ratios predicted by two drying models agreed well with experimental values. But in the actual range of drying temperature above 30$^{\circ}C$ Page model was more suitable for predicting of drying rates.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.16-23
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• 2017

This study aimed to determine the optimal harvesting time for covered barley to make grain silage, in Honam region of Korea. We harvested six varieties of barley every third day from 24 to 42 days after heading (DAH). The moisture content decreased from 62.4% at 24 DAH to 24% at 42 DAH. The moisture content at 36 DAH was 44.3%; however, moisture content at 39 and 42 DAH was lower than 40%. Yield of covered barley significantly increased from 24 to 42 DAH (p < 0.05). Yield at 36 DAH (557 kg/10a) was not significantly different from that at 39 and 42 DAH (p < 0.05). With respect to the feed value of barley grain silage, the amount of crude fiber and crude ash was different by harvesting time (p < 0.05). However, the amount of crude protein, crude fat, and total digestible nutrients (TDN) from 24 and 42 DAH was not significantly different. The pH of grain silage from 24 to 42 DAH was between 3.8 and 4.2 and it was stable until 36 DAH (p < 0.05). However, the pH of grain silage at 39 and 42 DAH was 5.2 and 5.8, respectively, which was higher than the pH of silage with good fermentation quality. The lactic acid content of barley grain silage from 24 to 42 DAH decreased from 5.5% to 0.5% (p < 0.05). The amount of lactic acid at 36 DAH was higher than that at 39 and 42 DAH (p < 0.05). With respect to moisture content, yield, feed value, and fermentation, the optimal harvesting time for grain silage of covered barley was 36 DAH. This could increase the use efficiency of harvesting machine for barley and reduce the harvesting time gap between whole barley silage and grain silage in Korea. Moreover, using barley grain silage for animal feed could reduce the import of corn.

• Korean journal of applied entomology
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• v.3
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• pp.27-30
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• 1964

The effects of the rice weevils(Sitophilus oryzae L.) on naked barley and wheat were studied in connection with the moisture contents and the molds in the grain under the controlled conditions; R.H. $75\%,\; 28^{\circ}C.$ 1. The moisture contents of control grain were decreased $2.07\%$ for naked barley and $1.29\%$ in wheat in four weeks. 2. The moisture contents of naked barley which had been infested with 100 weevils were decreased $0.29\%$ and were increased $0.79\% in the berley infested with 200 weevils at t beginning. In wheat, the moisture contents were decreased by$0.84\%\; and\; 0.13\%$ in respective experimental lots. 3. The moisture contents of grains have close relation with the population densities of the weevils in the grain. 4. The pattern of the change in the moisture content of grain have close relation with the population densities of the weevils in the grain. 5. The number of the mold colonies in the grain increased exponentially with the increase in the population densities of weevils in the grain. 6. The species of the mold found were A. restrictus and A. versicolor, which were the most abundant, and A. candidus was also found, but Ins common.

• 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 Food Hygiene and Safety
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• v.32 no.4
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• pp.321-328
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• 2017

Fusarium graminearum is a mycotoxigenic plant pathogen, which could remain in harvested barley grains and produces mycotoxins at preferable conditions during storage. To elucidate the factors affecting contamination of Fusarium and Fusariotoxin in hulled barley during storage, three hulled barley grain samples were collected from Jeolla province. Moisture content of each sample was adjusted to 14% and 20%, respectively, then stored in two warehouses where temperature was controlled differently: one controlled below $12^{\circ}C$, and the other with no control. While monitoring temperature and relative humidity of warehouses hourly, grain moisture content, Fusarium occurrence, and mycotoxin level was analyzed at 1, 3, 6, and 12 month after storage. The average monthly temperature and relative humidity ranged $3{\sim}29^{\circ}C$, and 58~70% in warehouse without temperature control, whereas $3{\sim}13^{\circ}C$ and 62~74% in warehouse controlled below $12^{\circ}C$. Grain moisture content of the samples decreased in both warehouses except 14% samples which increased in the warehouse with temperature control. Fusarium frequency of the contaminated grains decreased continuously in the warehouse without temperature control. But in the warehouse below $12^{\circ}C$, Fusarium decreasing rate was slower because of high grain moisture content. In most samples, nivalenol was detected more in the warehouse without temperature control after 12 month but there was little difference after 1, 3, and 6 month. Therefore, it will be efficient to store hulled barley in the warehouse controlled below $12^{\circ}C$ to reduce Fusarium contamination when the barley is not dried properly. In addition, when storage period exceeds 12 month, it is recommended to store hulled barley in a warehouse controlled below $12^{\circ}C$ to reduce nivalenol contamination.