• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.282-286
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• 1990

Currently, mechanization and automation have been introduced into rice harvest and drying process due to the shortage of man power. After rice cultivars, Chucheong and Milyang #23 were cutted with manual method (H1) or harvested with combine (H2), the threshed grain were dried in natural sun-drying (D1), in natural air in-bin system (D2), or in contineous hot-air drier (D3). We have evaluated grain losses, operation hour, and grain quality on each harvest and drying methods. Shattering loss during harvesting with combine was not dirfered significant from that of manual method, but threshing loss was 1.2% higher in combine harvest than in manual. Operation hours required for combine harvest was 3.5 times faster than for manual, even without head threshing. There was a significant difference bel ween cultivars in harvesting loss, which Milyang #23, a Tongil rice had two times more grain loss than Chucheong, a Japonica rice. Drying hours required to reduce to 14% grain moisture content were ten days for H1D1, 5-9 days for H2 D1, 2-3 days for H2D2, and only 15 hours for H2D3, respectively. In grain quality, complete grain ratio after dehulling was decreased about four percent in H2D3 compared to H1D1. while it was lower in Milyang #23 than in Chucheong, Hot-air drier increased occurence of cracked and broken grain. Combine harvest increased significantly these incomplete grain ratio of :Milyang #23, but not Chucheong.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.561-567
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• 2000

This study was conducted to determine the effect of far infrared-vacuum drying on the quality changes of Pimpinella bracycarpa, such as drying efficiency (weight loss), color differences, browning degrees, rehydration and sensory evaluation. Wehn Pimpinella bracycarpa was dried for designated time at 5$0^{\circ}C$, 6$0^{\circ}C$ and 7$0^{\circ}C$, drying time of far infrared-vacuum drying was decreased more than 17% compared to that of infrared drying. The color changes increased as drying temperature increased and far infrared-vacuum drying made less color changes than infrared drying. Also, the total microbial counts and the number of yeast and mold were gradually reduced as drying temperature increased and drying time was longer, but there was no significant differences in microbial changes among drying methods. The rehydration rates of Pimpinella bracycarpa increased as drying temperature increased and was better at far infrared-vacuum drying than infrared drying. Also, according to the sensory evaluation after rehydration of Pimpinella bracycarpa, the hihger scores were obtained at lower temperature and far infrared-vacuum drying, especially the color was obtained much hihger score in the far infrared-vacuum drying than infrared drying. Thus, the results showed that drying efficiency and stability of rehydration and color changes was increased and the quality deterioration of Pimpinella bracycarpa could be minimized by using far infrared-vacuum drying.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1283-1288
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• 1999

Effect of drying methods, such as natural solar drying, hot air drying$(at\;60^{\circ}C\;and\;105^{\circ}C)$, vacuum drying and freeze drying methods, on the quality of laver were investigated to develop optimum processing conditions for preparation of laver powder. Appreciable amount of laver pigments such as chlorophyll, carotenoid and phycobilin were lost during washing and drying process. Their loss was affected significantly by the method of drying. Among the methods tested, high temperature air drying was the worst in retaining laver pigment, while freeze drying was the best. Loss of vitamin C which was in the range of 75-99% was also affected by the method of drying. Isotherms for laver powder shelved sigmoidal shape and monomolecular layer moisture content of both laver powder(Porphyra dentata and Porphyra tenera) determined by the BET equation was 6.30%(dry basis). Laver powders prepared with Porphyra dentata and classified with 50-, 80- and 100- mesh sieves showed monomodal size distribution with the high frequency at 110-120, 100-110 and $80\;{\mu}m$, respectively, which indicated that size or laver powder was homogeneous.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.10
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• pp.743-748
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• 2013

The purposes of this study are to prepare Hanji fiber-filter sheets using replacement liquid in water-swollen fiber with non-polar solvent such as ethanol, methanol and pentane. The experiments were studied on the selection of optimal non-polar solvent and the optimal drying method for wetted fiber and then were to know physicochemical characteristics of prepared Hanji fiber-filter sheet. The Ethanol as liquid changer in water-swollen fiber was excellent solvent and the optimal drying method for them was freeze drying served with vacuum pump. The bulk density and porosity of prepared fiber sheet from freeze dryer were 0.11-0.13 g/mL, half of natural dried fiber sheet, and 90%, respectively. The results of SEM observation for the fiber sheet prepared with natural drying or heating drying were shown very close structure of fiber wall in dry state. However, the freeze drying sheet were shown the open structure. So, the head loss of freeze drying sheet was very lower than natural drying and heating drying sheets. From the results of BTEX removal experiments, the sheets dried at water wetted condition was shown more higher efficiency than the fiber sheets dried at solvent wetted condition.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.289-296
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• 2006

Various drying conditions, temperatures (40 to $80^{\circ}C$) and durations (overnight to 72 hrs), for the particulate organic matter (POM) fraction after wet-sieving size fractionation have been applied for determination of POM contents in the weight loss-on-ignition method. In this study, we investigated the optimum drying condition for POM fraction in quantification of POM and/or mineral-associated organic matter (MOM; usually indirectly estimated). The influence of the drying conditions on quantifying POM was dependent upon soil properties, especially the amount of soil organic components. In relatively high organic soils (total carbon > 40 g/kg in this study), the POM values were significantly higher (overestimated) with drying at $55^{\circ}C$ than those values at $105^{\circ}C$, which were, for example, 173.2 and 137.3 mg/kg, respectively, in a soil studied. However, drying at $55^{\circ}C$ for longer than 48 hrs of periods produced consistent POM values even though the values were much higher than those at $105^{\circ}C$. Thus, indirect estimates of MOM (MOM = SOM-POM) also tended to be significantly impacted by the dry conditions. Therefore, we suggest POM fractions should be dried at $105^{\circ}C$ for 24 hrs as determining POM and MOM contents. If the POM traction is needed to be dried at a lower temperature (e.g. $55^{\circ}C$) with a specific reason, at least 48 hrs of drying period is necessary to obtain consistent POM values, and a moisture correction factor should be determined to adjust the values back to a $105^{\circ}C$ weight basis.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.273-277
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• 2012

The vacuum drying process for drying of paper in current transformers was modeled with an aim to develop an understanding of the drying mechanism involved and also to predict the water collection rates. A molecular as well as macroscopic approach was adopted for the prediction of drying rate. Ficks law of diffusion was adopted for the prediction of drying rates at macroscopic levels. A steady state and dynamic mass transfer simulation was performed. The bulk diffusion coefficient was calculated using weight loss experiments. The accuracy of the solution was a strong function of the relation developed to determine the equilibrium moisture content. The actually observed diffusion constant was also important to predict the plant water removal rate. Thermo gravimetric studies helped in calculating the diffusion constant. In addition, simulation studies revealed the formation of perpetual moisture traps (loops) inside the CT. These loops can only be broken by changing the temperature or pressure of the system. The change in temperature or pressure changes the kinetic or potential energy of the effusing vapor resulting in breaking of the loop. The cycle was developed based on this mechanism. Additionally, simulation studies also revealed that the actual mechanism of moisture diffusion in CT's is by surface jumps initiated by surface diffusion balanced against the surrounding pressure. Every subsequent step in the cycle was to break such loops. The effect of change in drying time on the electrical properties of the insulation was also assessed. The measurement of capacitance at the rated voltage and one third of the rated voltage demonstrated that the capacitance change is within the acceptance limit. Hence, the new cycle does not affect the electrical performance of the CT.

• Korean Journal of Medicinal Crop Science
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• v.16 no.3
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• pp.188-191
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• 2008

Poncirus trifoliata Rafinesque has been used as the immature fruit of the trifoliate orange tree. This study was carried out to investigate the quality change of Poncirus trifoliata Rafinesque depending on packing materials (vacuum packing, PP (polypropylene) packing, gunny sack packing), storage places and storage periods up to 12 months. The change of loss on drying content, content of poncirin were measured during the 12 months. As a result, the loss on drying content was decreased rapidly in gunny sack packing after storage of 12 months at room temperature. The content of poncirin was decreased generally according to storage conditions and its average loss percent was 38.8%.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.67-74
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• 2001

A field experiment was carried out to determine the effects of chemical/mechanical treatments at mowing on the field drying rate and hay quality of alfalfa(Medicago sativa L., cv. Vernal) and spring oats(Avena satvia L., cv. Swan). The chemical drying agent of 2% $K_2CO_3$, mechanical mower conditioning, and no treatment(control) were treated for hastening hay-making in the spring of 1997. The forages were harvested at early bloom stage in alfalfa and heading stage in oats. After field dry, square bales were made by hay baler, and the dry matter(DM) loss, visual estimation and nutritive value of hay were evaluated after storing two months. The field drying rates of alfalfa and oats were high at mechanical treatment, but the drying effectiveness of chemical agents alone was very low. With mower conditioning, the duration of field dry was shortened by 1 day compared with control. therefore, mower conditioning enhance the field drying rate of alfalfa and oats. The DM loss of alfalfa and oats hay was reduced by mechanical treatment, but the efficiency by chemical alone was low. The visual score(leafiness, green color, odor and softness) of hay at mechanical treatment was slightly higher than that of chemical and control. The nutritive value(ADF, NDF, in vitro digestibility, and relative feed value) of hay was also high with treatment of mechanical, but those of chemical alone were similar compared with control. The nutritive value of hay after two months in both alfalfa and oats was decreased when compared with at harvest.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.725-731
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• 2004

A field test program was conducted for the newly placed concrete pavement of US Interstate Highway 10 between March 26th and 28th, 2003. The test section was located between Van Horn and Sierra Blanca in Hudspeth County approximately 130 km east of El Paso, Texas. The main objective of the test was collecting moisture-related data to validate the models of effective curing thickness, evaporation rate, and moisture-based maturity. Effect of moisture loss on drying shrinkage strain was studied using additional test instrumentation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.3
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• pp.259-266
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• 1998

A field experiment was carried out to determine the effects of mechanical and chemical drying agents at mowing on the field drying rate and hay quality of orchardgrass dominant pasture plants. The mower conditioner /chemical drying agent ($K_2CO_3$ 2% conditioning, $K_2CO_3$ 2% + conditioning and control) were treated at different harvest stages (late boot, heading and bloom stage) for hastening hay manufacture in 1996. After field dry, four square bales were made by hay baler, and the visual estimation and nutritive value of hay were evaluated after storing two months. The field drying rate of pasture plants was higher with delayed stage of harvest, and mechanical and mechanical + chemical, but chemical alone was very low. In mower conditioning, the duration of field dry was shortened by 0.5 to 1 day compared with $K_2CO_3$ and 1.5 to 2 days compared with control. The dry matter loss of hay was reduced by late harvest and mechanical, and mechanical + chemical, but the score by chemical alone was very low. The visual score (leafiness, green color, odor and softness) of hay after storage was high in mechanical and mechanical + chemical, but the score by chemical alone was very low. Nutritive value (ADF, NDF, digestibility, and relative feed value) of hay was also high with treatment of mechanical and mechanical + chemical, but the quality by chemical alone was similar compared with control. The quality of hay was very low when harvested at bloom stage. In conclusion, mower conditioning can enhance the field drying rate of orchardgrass dominant pasture plants, however the drying efficiency of chemical drying agent was very low. Harvesting at early heading to heading stage was recommened for manufacture of high quality hay.