• Journal of Biosystems Engineering
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• v.15 no.2
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• pp.99-109
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• 1990

Rough rice is subjected to a series of static and dynamic forces during mechanical harvesting, handling and processing operations. The mechanical properties such as bioyield point, compressive strength, and deformations at the bioyield point and rupture point are important engineering data needed to develop processing machines and to determine reasonable operating conditions for these machines. The objectives of this study were to determine the mechanical properties of the rough rice kernel at loading rate of 0.664 mm/min and 1.673 mm/min and at various moisture contents, and to examine the effect of the moisture content and the loading rate on these mechanical properties. The follwing results were obtained from the study. 1. Bioyield point, rupture point, bioyield strength and ultimate strength of the rough rice kernel generally decreased in magnitude with an increase in moisture content. A little larger values of these mechanical properties were obtained at the higher loading rate. The rough rice variety and the loading rate affected significantly these mechanical properties at low moisture content, but not at the higher moisture levels. 2. Bioyield point of the sample grains varied from 20 to 80 N, and rupture point varied from 45 to 130N. Bioyield point for Japonica-type rough rice was a little higher than that for Indica-type rough rice, but there were little differnces in rupture point between two types of rough rice. 3. Bioyield strength and ultimate strength of the Japonica-type rough rice varied from 10 MPa. to 39 MPa., and from 13 MPa. to 45 MPa. respectively. Those of the Indica-type rough rice varied from 12 MPa. to 42 MPa., and from 15 MPa. to 53 MPa. respectively. 4. Deformations at bioyield point and rupture point ranged from 0.18 mm/min to 0.26 mm, and from 0.28 mm to 0.53 mm respectively. These deformations decreased with an increase in moisture content up to moisture content of approximately 17% (w.b.) and increased again thereafter. 5. Regression equations were developed to predict these mechanical properties for the rough rice kernel as a function of moisture content.

• 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.

• Journal of Biosystems Engineering
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• v.23 no.4
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• pp.335-342
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• 1998

The objectives of this study were to evaluate respiration characteristics and develop empirical respiratory rate equations for short gain rough rice. The carbon dioxide concentrations generated from mush rice at four level temperatures(10, 20, 30, 4$0^{\circ}C$) and 4 level moisture contents(17.2, 21.5, 25.9, 31.6％, d.b.) were measured by gas chromatography. The respiratory rates' increased exponentially with gain temperature and also with moisture content The relationship between respiratory rate and gain temperature fitted the Arrehenius' and Core's equations very well. Two empirical respiratory rate equations were presented as a function of gain temperature and moisture content. The values of determination coefficient for the developed respiratory rate equations were 0.999, and the result of t-test showed that there were no significant differences between predicted and measured respiratory rates on significance level of 1%. Therefore, it appeared that respiratory rates predicted by the respiratory rate equations agreed well with measured values. An equation for predicting dry matter losses of rough rice during storage was presented by modifying the respiratory rate equations based on chemical reaction of decomposition of carbohydrate.

• Journal of Biosystems Engineering
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• v.11 no.2
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• pp.55-65
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• 1986

The resistance to the passage of airflow through various agricultural products is an important consideration in the design of an aeration or drying system. The amount of resistance to airflow varied widely from one kind of grain to another, and depended upon airflow rate, surface texture and shape of the particles, the size and configuration of voids, and foreign and fine material in the grain bed. The airflow rate was the major factor considered on this kind of study in the early stages. But these days, the studies on the resistance to airflow of grain affected by grain moisture content and foreign and fine material have been widely carried out. However the foreign an fine material in the grain bed could not be a major factor on the study in Korea because there were only a few grain process procedure after harvesting it. The objectives of this study were to investigate the effect of moisture content and airflow rate on airflow resistance to grain, and to develop a model to predict the static pressure drop across the grain bed as a function of moisture content and airflow rate. The rough rice varieties, Akibare, Milyang 15 (Japonica types), Samkwang, Backyang (Indica types)and covered barley variety, Olbori, which were harvested in 1985 were used in the experiment after cleaning them. Resistances to airflow of grain were investigated at four levels of moisture content (13-25%, wb.) for ten different airflow rates($0.01-0.15m^3/sm^2$). The results of this study are summarized as follows; 1. Theaverage bulk densities were $585.3kg/m^3$ for rough rice and $691.6kg/m^3$ for barley at the loose fill, and were $648.8kg/m^3$ for rough rice and $758.2kg/m^3$ for barley at the packed fill. The pressure drops at the packed fill beds were approximately 1.4 to 1.8 times higher than those at the loose fill beds. 2. The pressure drops across grain beds deceased with the increase of moisture content and increased with airflow rate. The decreasing rates of pressure drop across grain beds according to the moisture contents at the lower airflow rates were higher than those at the higher airflow rates, and the increasing rates of pressure drop according to the airflow rates at the lower moisture contents were higher those at higher moisture contents. 3. The pressure drop across barley bed were much higher than rough rice beds and the pressure drops across Japonica type rough rice beds were a little higher than Indica type. 4. The mathematical models to predict the pressure drop across grain beds as a function of moisture content and airflow rate were developed from these experiments.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.140-146
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• 2013

This experiment was conducted in order to study the physiological characteristics of Sedum takevimense in different moisture conditions. The photosynthetic rate, water use efficiency and the respiratory rate were determined by using a photable photosynthesis system. According to the results, the best illumination range and moisture range were explicitly selected. The highest photosynthetic rate was at $600{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and after this value, the trend showed a reduction. When the moisture was 11.31%, the photosynthetic capacity and water use efficiency reached maximum value, but the respiratory rate reached maximum value at 7.91%. According to the measured values, the best illumination range was $600{\sim}1,200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and the best moisture range was 7.09~11.31%.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.1
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• pp.61-70
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• 2001

As important factors determining human sensorial comfort, liquid moisture management and surface properties of heat resistant workwear materials were examined. To figure out liquid moisture management properties of the test materials, absorption capacity, rate of absorption, and evaporation properties were assessed. A modified GATS(Gravimetric Absorbency Testing System) was used to measure the liquid moisture accumulation associated with the wicking of liquid moisture from sweating skin. The GATS procedure measures demand wettability of materials to take up liquid in a direction perpendicular to the fabric surface and it was modified to incorporate a special test cell and cover to assess absorption behavior in the presence of evaporation. Fabric stiffness, smoothness, number and the length of surface fibers, and an estimate of the contact area between the skin and fabric surface were measured to characterize the mechanical and surface properties of the test materials. Also an estimate of the force with which a fabric clings to moist skin was made using as wet-cling index.

• Journal of Biosystems Engineering
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• v.21 no.1
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• pp.60-71
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• 1996

The purposes of this study were to develop a simulation model and to determine minimum specific airflow rate requirements for natural air drying of rough rice in Korea. A simulation model was developed considering energy and mass balances within grain bed, drying and rewetting rates, and hysterisis effect between sorption and desorption isotherms. As the results of validation test, the moisture contents predicted by the model agreed very well with the actual data. The criteria for determining minimum specific airflow rate requirements was that the top loom layer in the bin be dried to a moisture content below 16 percent wet basis with less than 0.5% drymatter decomposition. The minimum specific airflow rate requirements in 13 locations of Korea were presented based on the worst one among the past 7 to 13-year weather data. These requirements were also presented for all the combinations of three harvest dates and four harvest moisture contents. Specific airflow rate requirements seemed to be half by each 2 percent reduction in moisture content from 24 percent. As harvest date was delayed by 10 days from October 1, these requirements were reduced by about 20 to 40 percent.

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.360-363
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• 1989

The initial moisture adsorption of soybeans was examined under the conditions : RH, 57-86% ; temperature, $16^{\circ}-34^{\circ}C$, and storage time, 100 hours. The changes in moisture content as a function of time held a relation: log dw/dt=b log t + log a, where w is the moisture content (%, db), t is time (hour) and a and b are the parameters which were calculated from the experimental data. The calculated moisture content from the equation agreed well with the measured moisture content. The activation energy of initial adsorption rate was about 15500cal/g-mole in all soybeans. The initial adsorption rate at temperature $16^{\circ}-28^{\circ}C$ could be estimated from a following equation : log(log dw/dt)=-15500/2.303RT.

• Journal of the Korean Wood Science and Technology
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• v.25 no.4
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• pp.99-107
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• 1997

This study was executed to test the possibility of replacement for domestic Japanese larch(Larix leptolepis) for hardwoods and to acquire the information about the effects of drying temperature on internal temperature, moisture content and drying defects. In high-temperature drying, internal temperature increased rapidly to boiling point, immediately after that point the internal temperature rising rate was reduced. In the case of drying at temperature of $125^{\circ}C$, internal temperature could reach at boiling point in a very short time. Moisture content in high-temperature drying showed constant drying rate period and first period of falling rate drying together in 4 hours since experiment begun. There was no strong correlation between initial moisture content and final moisture content. Average drying rate at $115^{\circ}C$, $120^{\circ}C$ and $125^{\circ}C$ was 1.42%/hr, 1.88%/hr and 2.02%/hr, respectively; the case of drying temperature of $125^{\circ}C$ showed most rapid drying rate. Drying rate of $125^{\circ}C$ was so rapid that it showed more severe shrinkage, bow, collapse, end check, and internal check development than in other drying conditions. The result of this study showed the strong possibility of high-temperature drying for Japanese larch, and to dry Japanese larch optimally, dry bulb temperature should not exceed $120^{\circ}C$.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.105-110
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• 2011

This study determined the effects of the dietary moisture level and feeding rate on the growth and gastric evacuation of young olive flounder. Four experimental diets with different moisture levels (9%, 21%, 30%, and 40%) were prepared through the addition of water to the commercial extruded pellet. Three replicate groups of fish (initial weight: $106{\pm}1.4\;g$) were fed diets containing 9%, 21%, 30%, and 40% moisture to satiation or a moisture level of 9% and 30% at a restricted feeding rate (95% of satiation) for 15 weeks. The mean water temperature was $22{\pm}1.6^{\circ}C$ during the feeding trial. Gastric evacuation rates were determined post-feeding. The dietary moisture levels did not significantly affect weight gain, but the weight of the fish receiving 9% and 30% moisture diets to 95% satiation were significantly lower than those of the fish fed 9-40% moisture diets to 100% satiation (P<0.05). The feed efficiency, protein efficiency ratio, viscerosomatic index, and survival were not significantly affected by the dietary moisture levels and feeding rates. The daily feed intake of the fish fed to 100% satiation did not significantly differ among the treatment groups. The stomach contents that peaked within 3 h of feeding gradually decreased, and the stomachs of fish were completely evacuated within 18 h. The contents of the intestine peaked at 3-12 h post-feeding, and then declined with the intestine being mostly evacuated at 30 h. The moisture of the stomach contents reached approximately 70% within 3 h post-feeding and gradually increased to approximately 75% within 12 h. No considerable differences were observed in the gastric evacuation and moisture levels of the stomach contents in the fish fed the different diets. The results of this study suggest that the gastric evacuation of olive flounder was not affected by the dietary moisture level and that the addition of water into the diet displayed no beneficial effects on the growth of young olive flounder.