• Applied Biological Chemistry
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• v.24 no.1
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• pp.29-39
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• 1981

Cooked spaghetti soaked in 10%, 20%, and 40% aqueous glycerine solutions for ten minutes absorbed sufficient glycerine to plasticize that spaghetti during and after subsequent drying. The plasticizing action of the glycerine prevented fissuring(checking) and surface corrugation of the spaghetti at elevated drying temperature and large wet-bulb dry-bulb temperature difference. The drying temperature and the wet-bulb dry-bulb differences up to which such protection was provided as the glycerine soak concentration increased. Despite the reduction in drying rate, the drying time required to produce spaghetti with a water activity of 0.65 (the level normally required for stability) decreased as glycerine content increased. At high frying temperatures glycerine addition increased the extent of browning and shortened the period required to induce detectale browning, but in all instances browning started well after the product $a_w$ reached the 0.65 value required for the completion of drying. Because glycerine addition reduced drying times at any given set of drying conditions and permitted the use of higher drying temperatures, relatively low levels of glycerine addition (e.g. 0.15 kg glycerine/kg dry spagetti) can shorten spagnetti drying times by roughly 80% and perhaps by as much as 93%.

• Journal of Biosystems Engineering
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• v.35 no.6
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• pp.401-407
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• 2010

In this study, computer simulations were conducted to assess the use of a circulating concurrent-flow dryer for rapeseed drying and to determined the effect of this drying method on the germination ratio of rapeseed after the drying process was complete. The simultaneous heat and mass transfer between air and rapeseed in a concurrent-flow dryer was examined by simulation. The drying simulation was based on several parameters with sequent time series. Equations concerning air psychrometrics, physical properties, thermal properties, equilibrium moisture content, thin layer drying of rapeseed, etc. were all combined to solve the simulation models. Based on energy and mass transfer in the concurrent-flow drying model, a simulation program for the circulating concurrent-flow rapeseed dryer was built along with a detailed description of the mathematical solution to the model. A pilot scale circulating concurrent-flow dryer(200 kg/batch) was used to verify the fitness of the simulation program. A comparison between the experimental data and the model predicted results was presented and discussed. The drying parameters and germination ratio were analyzed and the accuracy of the simulation program was evaluated. The simulation program proved to be reliable and was shown to be a convenient tool for predicting rapeseed drying and germination ratio of rapeseed in a concurrent-flow dryer.

• The Korean Journal of Food And Nutrition
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• v.35 no.6
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• pp.426-434
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• 2022

In this study, the effect of osmotic drying conditions of mangoes on hot air drying was investigated. Four different osmotic agents of 60 Brix, such as S60, SM10, HF80, and SG25, were prepared. Mango slabs were osmotically dried with the agents at a ratio of 1:4 (w/w) for up to 8 hours. SG25 showed the lowest weight reduction and moisture loss during the process. As a result of hot-air drying, all samples showed a high correlation with the Page model (0.9761~0.9997), and the required drying time of all samples that were osmotically dried was reduced compared to the non-osmotically dried group. After hot-air drying, the pH value increased according to the drying temperature. The L, a, and b values and the total polyphenol content also decreased. Through this study, the possibility of osmotic drying was confirmed to increase the efficiency of hot air drying of mangoes, which is expected to contribute to the industrial use of domestic mangoes.

• Journal of Korean Society of Forest Science
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• v.37 no.1
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• pp.17-30
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• 1978

Press drying was used on italian poplar (Populus euamericana) to find the profitable means of drying. This study was designed to investigate the process of platen drying considering core temperature, drying time, current moisture content, drying rate, shrinkage and recovery, and green volume specific gravity, equilibrium moisture content and dimensional stability of press dried material and air dried material, The drying tests were conducted using 1.5 centimeter thick material at platen temperature of $175^{\circ}C$. The results were summarized as follows. 1. Core temperature was divided into three stages of drying characterized by period initial heating, plateau temperature and rising core temperature. Plateau temperature was 114 to $119^{\circ}C$. 2. The following predicting equations of drying time(y) in different core temperatures were developed for initial thickness($x_1$), initial moisture content ($x_2$) and final moisture content ($x_3$) 3. The predicting equaltion of current moisture content(u) was log u=4.658-0.060t as funtion of drying time(t) and that of drying rate(r) was log r=-2.797-0.049t. Current moisture content and drying rate of air drying were shown in figure 2. 4. The predicting equation of shrinkage in thickness direction(y) was log y=1.933+0.038t as function of drying time(t), and that of expansion in width direction was $y=-0.692+0.043t-0.001t^2$. 5. Thickness shrinkage was increased more than proportional at to pressure increase. Width shrinkage and thickness recovery was greatest at 35psi. 6. Green volume specific gravity of press dried material was 25% greater than that of air dried material. But equilibrium moisture content of press dried material was less 24% than that of air dried material. Antishrinkage efficiency of press dried material were obtained 27.7%.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.237-246
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• 2018

Purpose: This study (a) investigated the effect of microwave power intensity and sample thickness on microwave drying characteristics of radish strips, and (b) determined the best-fit drying model for describing experimental drying data, effective moisture diffusivity ($D_{eff}$), and activation energy ($E_a$) for all drying conditions. Methods: A domestic microwave oven was modified for microwave drying and equipped with a small fan installed on the left upper side for removing water vapor during the drying process. Radishes were cut into two fixed-size strip shapes (6 and 9 mm in thickness). For drying experiments, the applied microwave power intensities ranged from 180 to 630 W at intervals of 90 W. Six drying models were evaluated to delineate the experimental drying curves of both radish strip samples. The effective moisture diffusivity ($D_{eff}$) was determined from Fick's diffusion method, and the Arrhenius equation was applied to calculate the activation energy ($E_a$). Results: The drying time was profoundly decreased as the microwave power intensity was increased regardless of the thickness of the radish strips; however, the drying rate of thicker strips was faster than that of the thinner strips up to a certain moisture content of the strip samples. The majority of the applied drying models were suitable to describe the drying characteristics of the radish strips for all drying conditions. Among the drying models, based on the model indices, the best model was the Page model. The range of estimated $D_{eff}$ for both strip samples was from $2.907{\times}10^{-9}$ to $1.215{\times}10^{-8}m^2/s$. $E_a$ for the 6- and 9-mm strips was 3.537 and 3.179 W/g, respectively. Conclusions: The microwave drying characteristics varied depending on the microwave power intensity and the thickness of the strips. In order to produce high-quality dried radish strips, the microwave power intensity should be lower than 180 W.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.577-583
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• 1998

Chestnut and paulownia boards for the traditional musical instruments were air dried to compare moisture contents(MC), drying rates and drying times between the air drying for 70 days in a yard and the shed drying for 150 days in a closed shed when piled in early June. An average final MC and the drying rate of chestnut boards were 20.6 percent and 0.78%/day for the air drying, and 16.6 percent and 0.44%/day for the shed drying. An average final MC and the drying rate of paulownia boards were 16.7 percent and 1.53%/day for the air drying, and 13.5 percent and 0.77%/day for the shed drying. Drying rates of air-dried boards were nearly twice as high as those of shed-dried boards for both species. Air drying rates of chestnut and paulownia boards were very high and exhibited falling drying rate above the fiber saturation point(30%), and then decreased irregularly. However, shed drying rates of chestnut and paulownia boards were high and exhibited falling drying rate above 55 percent MC for chestnut boards and above 80 percent MC for paulownia boards, and then decreased irregularly.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.1
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• pp.28-42
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• 2017

Moisture transfer characteristics of high emotional garments are important to evaluate wear comfort. Wicking and drying measurement methods are also critical for perspiration absorption and quick dry fabric made of high functional fibers. In this study, the wicking and drying properties of high emotional fabrics made from hybrid composite yarns using CoolMax, Tencel, Bamboo staple fibers and PP. PET CoolMax filaments were also measured and analyzed according to various measuring methods. The wicking property of hybrid composite yarn fabrics by Bireck method was mostly influenced by the structure of hybrid yarns than the absorption rate of constituent fibers; however, both the hygroscopicity of fibers and the composite yarn structure affected the wicking property of the fabrics in the drop method. Concerning drying properties, the KSK 0815B method measuring distilled moisture weight was more relevant to explain the drying characteristics of hybrid yarn fabrics than the KSK 0815A method measuring the time to drying. This study revealed that the drying properties of hybrid yarn fabrics were influenced by the hygroscopicity of constituent fibers, wicking properties of constituent yarns and structure of composite yarns.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.771-777
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• 2007

Sliced and whole root of rehmannia were dehydrated in a laboratory dryer at 40, 60, 80, and $100^{\circ}C$ to evaluate the kinetic parameters for dehydration of rehmannia. The drying curves of both samples were characterized by a falling-rate drying period only. Sliced rehmannia dried 1.1 to 3.1 times faster than whole root of rehmannia depending on drying temperature. Equilibrium moisture content (EMC) of rehmannia samples at the drying temperature tested were 0.069-0.078 g water/g dry solid, which was coincided with the monolayer moisture content (0.06 and 0.07 g water/g dry solid) evaluated from desorption isotherms using GAB (Guggenheim-Anderson-de Boer) model. A logarithmic model for thin layer drying was applied to evaluate the drying time to reach EMC ($t_{EMC}$) and drying constant (k). The effect of temperature on $1/t_{EMC}$ and k was described by the Arrhenius model with activation energy values of 32.56 and 47.14 kJ/mol determined using the former parameter, and 34.27 and 38.26 kJ/mol determined using the latter parameter for sliced and whole root of rehmannia, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.207-210
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• 1982

For the removal of initial water content in cuttlefish, the effects of fixed-bed drying condition on the drying rate were investigated, with following results. 1. The drying rate of cuttlefish dried at fixed-bed condition was also faster than that at natural convection type or hot air dryer.2. By controlling air temperature and its direction to cut-and-peeled sample the drying time can be reduced to 2 hrs. 3. Shirai's equation and Arrhenius' law were applicable to fixed-bed dried cuttlefish. Drying rate constant (k) by Shirai's equation, and Arrhenius' plot were as shown in Table 3, 4 and Fig.3, respectively.

• Journal of Korean Society for Quality Management
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• v.44 no.3
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• pp.487-508
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• 2016

Purpose: Current testing method for drying rate used in military textiles has different results according to the public testing institute. So the purpose of this study was to suggest the alternative method which secure the reliability of the drying rate test. Methods: We measured the drying rate by various test methods for military clothes 14 species including quick drying function and compared the test results. Also, the collected data through the test was analyzed using one-way ANOVA. The p-value of results was compared by various testing institutions. Results: The results of this study are as follow; A deviation occurred among the testing institutions in original test method(KS K 0815). Whereas it is verified that there is no deviation among the institutions in 5% significance level by another test method(ISO 17617). Also it would increase work efficiency by reducing the testing time required to test by using ISO 17617. Conclusion: Based on the results, we can suggest the reliable test method of the drying rate.