• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.866-871
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• 1997

This study was carried out to determine the effect of osmotic dehydration as pretreatment on the qualities of dried cherry-tomatoes. The weight reduction and solid gain in osmosed cherry-tomato were increased by increasing sugar concentration, immersion temperature and time; among three parameters, the immersion temperature affected more than sugar concentration and immersion time did. The moisture content was decreased as increasing sugar concentration, immersion temperature and time, and it was the lowest at the osmotic conditions of 7$0^{\circ}C$, 60$^{\circ}$Brix and 11hr. To determine the optimum processing condition by RSm, the polynomial optimum models were established. The regression models was significant (p<0.05). It was used contour plots to optimize osmotic dehydration. The optimum condition for osmotic dehydration as pretreatments for drying of cherry-tomatoes were immersion temperature of 47~53$^{\circ}C$, sugar concentration of 39~43$^{\circ}$Brix, and immersion time of 7hr, in which process conditions were 78~86% moisture content, 8.5~10$^{\circ}$Brix sugar content and 80~86% weight reduction.

• Journal of Biosystems Engineering
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• v.11 no.2
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• pp.14-22
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• 1986

This study was carried out to find a method which can be used to measure the soil moisture content of the soil bin exactly and quickly. And gypsum block is used as an instrument in measuring soil moisture content in the field of green house farming, etc.. However the characteristics of gypsum block, or the guide line of making gypsum block is not well introduced in Korea. So the information about gypsum block such as the density of gypsum, type of electrode, dimension of electrode, distance between electrodes, density of surrounding soil were included in this study and their effects on the relationship between soil moisture content and electrical resistance were investigated. The results of this study are as follows; 1. The grid type electrode was quicker in accessing the equilibrium condition and showed more sensitive response to the change of soil moisture content than the plate type electrode. 2. The longer the distance between the electrodes, the larger the electrical resistance, and the distance of 3 to 5 mm was recommended. 3. The larger the width of the electrode, the smaller the electrical resistance. However, there was no significance between the levels designed in this study. Considering the size of the gypsum block itself, the adaptible range of width may be 4 to 8 mm. 4. The higher the density of gypsum, the smaller the electrical resistance. And the block of lower density was broken down in the soil of higy moisture content. The optimum ratio of gypsum to water was 7:5. 5. The measuring system used in this study allowed simultaneous, multi-data acquisition. So this system using A/D converter can be applied to the measurement of soil moisture content of soil bin.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.6
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• pp.99-110
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• 1997

The study was conducted in order to investigate the basic geotechnical properties of sand-bentonite mixtures with the various bentonite contents. The results obtained are as follows : 1. Optimum moisture content of sand-bentonite mixtures was approximately 17.10~18.52% corresponding to the maximum dry density of 1.58~1 .64gf/$cm^3$. As the bentonite contents and curing peroid increased, both the maximum dry density and optimum moisture content of sand-bentonite mixtures increased. 2. The unconfined compressive strength of sand-bentonite mixtures increased as the increase of bentonite content, but it did not change along the curing period. 3. The sand-bentonite mixtures ruptured at 8~15% of the axial strain and the maxi-mum shearing stress was about O.7Okgf/$cm^2$. 4. According to the increase of bentonite content, the cohesion intercept and internal friction of the sand-bentonite mixtures increased slightly in the shear test, while the cohesion intercept increased largely, and the internal friction angle decreased largely in the triaxial test. 5. Both the initial void ratio and swelling of the sand-bentonite mixtures were very low with respect to the consolidation pressure increase. 6. The swelling and shrinkage of sand-bentonite mixtures increased slightly according to the increment of bentonite content.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.885-890
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• 1995

Ten Korean rices were cooked at various moisture contents($57.5{\sim}69.5%$) and the sensory characteristics including appearance, flavor, texture and overall desirability were evaluated. The clumpiness, firmness and moistness of the cooked rice were significantly affected by moisture content in all samples. The optimum moisture content of the cooked rice was 66.5%. The rices cooked at optimum moisture content showed differences among varieties in off-odor, glossiness and color and no differences in other sensory characteristics(p<0.05).

• Journal of Industrial Technology
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• v.29 no.A
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• pp.145-153
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• 2009

In this study, to determine characteristics of compaction and the soil water characteristic curve(SWCC) in decomposed granitic soils, compaction tests and SWCC tests were carried out for samples having various contents of coefficient of uniform($c_u$), By compacting their samples with standard Proctor density test, the effects of binder contents on maximum dry density and optimum moisture content were investigated and compared. Samples compacted with the maximum dry density and the optimum moisture content were tested by means of the SWCC, to determine their SWCC parameters, such as Brooks & Corey(${\lambda}$, ${\Psi}_b$), Van Genuchten (${\alpha}$, n, m), Fredlund & Xing(a, n, m).

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3815-3832
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• 1975

This study was made to investigate various engineering properties of earth materials resulting from their changes in density and moisture content. The results obtained in this study are summarized as follows: 1. The finner the grain size is, the bigger the Optimum Moisture Content(OMC) is, showing a linear relationship between percent passing of NO. 200 Sieve (n) and OMC(Wo) which can be represented by the equation Wo=0.186n+8.3 2. There is a linear relationship of inverse proportion between OMC and Maximum Dry Density (MDD) which can be represented by the equation ${\gamma}$d=2.167-0.026Wo 3. There is an exponential curve relationship between void ratio (es) and MDD whose equation can be expressed ${\gamma}$d=2.67e-0.4550.9), indicating that as MDD increases, void ratio decreases. 4. The coefficent of permeability increases in proportion to decrease of the MDD and this increase trend is more obvious in coarse material than in fine material, and more obvious in cohesionless soil than in cohesive soil. 5. Even in the same density, the coefficient of permeability is smaller in wet than in dry from the Optimum Moisture Content. 6. Showing that unconfined compressive strength increases in proportion to dry density increase, in unsaturated state the compacted in dry has bigger strength value than the compacted in wet. On the other hand, in saturated state, the compacted in dry has a trend to be smaller than the compacted in wet. 7. Even in the same density, unconfined compressive strength increases in proportion to cohesion, however, when in small density and in saturated state, this relationship are rejected. 8. In unsaturated state, cohesion force is bigger in dry than in wet from OMC. In saturated state, on the other hand, it is directly praportional to density. 9. Cohesion force decreases in proportion to compaction rate decrease. And this trend is more evident in coarse matorial than in fine material. 10. Internal friction angle of soil is not influenced evidently on the changes of moisture content and compaction rate in unsaturated state, On the other hand in saturated state it is influenced density. 11. Cohesion force is directly proportional to unconfined compressive strength(qu), indicating that it has approximately 35 percent of qu in unsaturated state and approximately 70 percent of qu in saturated state.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.64-67
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• 1980

Field experiments were conducted to determine the optimum harvesting time and to evaluate the effect of Diquat spray in late seeded sesame, cultivar 'Suweon 9'. Sesame seed yield reached a plateau from Sept. 18 harvest when seed number was maximum. Thousand seed wt. increased to Sept. 29 harvest. As harvesting was delayed moisture content of capsule decreased and capsule dehiscence increased. Capsule dehiscence did not start until its moisture content dropped below 70%. Optimum harvesting might begin from the time which moisture content of capsule dropped below 70%, leaf senescence reached upper node, and 50% of capsules lost green. About 5% increase in seed weight after defoliation was estimated to be translocation from capsule wall. Diquat spray with 0.3% and 0.5% (v/v) solution of commercial Reglone (20%in A.I.) decreased rapidly capsule moisture content and promoted seed shattering. Dehiscence in 90% capsules was noted at seven days after Diquat spray. Diquat spray as a harvest aid could accelerate sesame desiccation up to 2 wks from normal field condition.

• Journal of Biosystems Engineering
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• v.16 no.3
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• pp.248-262
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• 1991

Simulation model was developed to analyze drying process for tray type red pepper dryer and validated by experiments. This model could predict satisfactorily temperatures and moisture contents of red pepper and temperatures of drying air during drying. Optimize algorithm was developed to search control valiables (drying air temperature, air recycle ratio and air flow rate) of red pepper dryer based on a criterion of minimizing energy consumption under the constraint conditions that statisfied carotenoid retension of at least 210mg per 100g dry matter, the moisture content of bottom layer of 15% (d.b) and drying time of less than 35 hours. Step changes in drying air temperature and air recycle ratio were considered in the optimization. In single step in control variables, the difference of the moisture content between top layer and bottom layer was great and more fan power was required. As the drying trays were exchanged when the moisture content of bottom layer reached to 100% (d.b), fifty percent of energy was saved and the difference of moisture content was little. In double step changes in control variables, optimal conditions were found by changing the step when the moisture content of bottom layer reached to 100% (d.b) (about 19.8 hours from starting drying). Optimum air flow rate was $18.1cmm/m^2$. Optimum drying air temperature and air recycle ratio in the first step was $55.8^{\circ}C$ and 0.80, and in the second step $65.6^{\circ}C$ and 0.88, respectively. In triple step changes in control variables, the optimal conditions were found by changing the steps when the moisture content of bottom layer reached to 250% (d.b) and 150% (d.b). Optimal air temperatures were $66.2^{\circ}C$, $58.4^{\circ}C$ and $66.9^{\circ}C$, and optimal air recycle ratios were 0.778, 0.785, 0.862 at each step, respectively. Optimal air flow rate was $18.9cmm/m^2$. The best operating mode was triple step mode considering energy consumption, drying time, fan power, and quality of dried red pepper. When the triple step mode was used to dry the red pepper, the energy consumption was about 16.5%~57.2% less than that of the single step mode and the drying time was 6.6 hours shorter than that of the double step mode.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.4
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• pp.2761-2769
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• 1972

The following results were obtained by the compression test of 3, 7, 14 and 28 days cured lime soil mixtures. The soil used in this test was clayey soil(sand : 20% silt : 45%, clay : 35%) and the rates of hydrated lime mixture for the dry weight of soil were 4, 8, 12, 19 and 20 percents. 1. The optimum moisture content increases and the maximum dry density decreases with the increase of the lime content. 2. The compacted moisture for the maximum strength in lime soil mixture increases with the increase of the lime content and the increase of curing periods. 3. The compressive strength increase of curing periods and its increasing ratio is largest at the 8 percent lime content. 4. The line content for the maximum strength decreases with increase of curing period and the largest strength shows at the 8 percent lime content when the curing period is over two weeks. 5. It seems to depend on the temperature effect that the compressive strength of lime soil mixtures cured in soil shows the lowest value. Accordingly, the effect of curing moisture does not influence to the strength of lime soil mixtures as much as the variation of curing temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.1
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• pp.30-34
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• 1984

A pot experiment was conducted to investigate the dry matter weight of soybean plant, fertilization efficiency, and the changes of p uptake with different p application levels in cultivated and uncultivated soils controlling the soil moisture content to 2 levels. 1. The effect of irrigation was higher in cultivated soil than in uncultivated soil, and was higher in larger amount of p application than in small amount of p. 2. Efficiency of phosphate fertilization for soybean growth was higher in cultivated soil compared with uncultivated soil, and increased by irrigation to optimum soil moisture content for crop growth. 3. Adjustment of soil moisture content to optimum level for soybean growth increased the concentration of phosphate in plant and decreased the content of phosphate in soil. Therefore, it was obvious that soybean plant absorbed the high amount of p in the optimum soil moisture level and in large amount of p application.