• Journal of the Korean Wood Science and Technology
• /
• v.43 no.6
• /
• pp.746-756
• /
• 2015

The goal of this study was to review the wood shrinkage published in Journal of The Korean Wood Science and Technology from 1976 to 2015. Previous studies reported that shrinkage from Larix kaempferi in the tangential, radial, longitudinal directions ranged from 4.21%-9.79%, 2.09%-4.67%, 0.17%-0.33%, respectively. When different drying methods including closed cylinder drying, oven drying, and room temperature drying were used, volumetric shrinkage of Dipterocarpus grandiflorus was different, ranging from 31.6% to 21.0%. With an increment of the drying temperature of $115^{\circ}C$, $120^{\circ}C$, $125^{\circ}C$, the shrinkage of Larix kaempferi did not show a consistent trend. When sample size of Pinus densiflora was increased from $20{\times}20{\times}20mm$ to $100{\times}100{\times}100mm$, the tangential, radial and volumetric shrinkage decreased 2.61%, 1.32%, 0.80%, respectively. When a caliper having a sensitivity of 0.01 mm was used to measure $20mm^3$ specimen from Cryptomeria japonica, the measurement error occurred 1.97% in the radial direction and 35.7% in the longitudinal direction. From the previous studies, wood shrinkage could be influenced by sample size, drying method and measurement technique.

• International Journal of Highway Engineering
• /
• v.6 no.4 s.22
• /
• pp.109-121
• /
• 2004

This study was performed to investigate the characteristics of drying shrinkage for concrete slabs as a project for Korean pavement design procedure. According to the volume-surface ratios and aggregate types, the experiments have been executed for 252 days. In order to simulate the volume-surface ratio of a real concrete pavement slab, three-layer epoxy coating and wrapping were used to prevent the evaporation at the part of specimen surfaces. As a result of preliminary test, coating and wrapping method was identified as reliable for three months. According to the volume-surface ratio, the drying shrinkage of the concrete specimen using sandstone was measured 1.32 to 1.8 times higher than that of the limestone specimen. Comparing to the measured drying shrinkage strains and established ACI and CEB-FIP model equations, it turned out that those model equations were underestimated. Finally, considering the age and volume-surface ratios, the prediction equations of the drying shrinkage of concrete specimen were proposed through a multiple nonlinear regression analysis.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.5
• /
• pp.102-108
• /
• 2016

The purpose of this study is to examine the reduction effect of shrinkage reducing agent for drying shrinkage induced cracking and suggest the method of controlling the cracking in concrete box culvert for power transmission. Based on drying shrinkage cracking mechanism, it is necessary to perform the numerical analysis, which involves shrinkage reducing effect of shrinkage reducing agent. From the numerical results, it is found that cracking behavior for longitudinal direction and transverse direction due to differential drying shrinkage of box culvert can occur and the experimental observation of concrete cracks support the numerical predictions. The shrinkage reducing agent reduced the concrete cracking by 40~50%, which shows the methodology of controlling of drying shrinkage cracks in box culverts in real construction site.

• The Korean Journal of Food And Nutrition
• /
• v.31 no.6
• /
• pp.933-939
• /
• 2018

The objective of this study was to determine the effects of drying methods on the quality characteristics and antioxidant activities of pumpkin (Cucurbita moschata Duch.). Pumpkins were dried naturally ($25^{\circ}C$), hot-air drying ($60^{\circ}C$), and throgh freeze drying ($-40^{\circ}C$) methods. The moisture activities were highest in the freeze dried group. The soluble solid showed no significant differences among all groups. The pH was highest in the freeze dried group. The L values were increasing in freeze dried group, whereas the b values were increased in hot-air dried group. The free sugar was highest in freeze dried group. The DPPH radical scavenging activity of hot-air dried group was higher than those of the other groups. The ABTS radical scavenging activities were highest with hot-air dried group and freeze dried group. It was established that hot-air dried group is the most effective drying method for the production of high quality dried pumpkin.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.24 no.2
• /
• pp.1-10
• /
• 2022

The purpose of this study is to analyze the structural properties of 100% wool fabrics knitted with various stitch types and to evaluate dimensional stability from shrinkage in wet cleaning and drying. Materials were weft-knitted from twenty-four different stitches with 7 gauge using a computerized flatbed knitting machine. Weight, thickness, density, and length were measured. A domestic washing machine and a tumble dryer were used for the shrinkage test. The results are as follows: Knitted fabrics were divided into 3 groups based on weight per unit area. Porous knits show light weight whilst milano, pintuck, rib stitches belong to the heaviest group. A positive correlation between weight and thickness was found and the same result was obtained for wale density and weight. Dimensional shrinkage of knitted fabrics was increased during repetitive wet cleaning and drying regardless of knit stitches. Especially, fabrics knitted with float, tuck, cable, and links & links stitches samples were contracted more than 15% in the first treatment whereas 2x1 rib stitch showed 1% shrinkage rate. Fisherman and milano stitches contracted in both course and wale direction with similar shrinkage rates. However, porous knits with float and tuck stitches shrank in course direction by 20% as well as cable samples contracted from 5% to 20% after repeated washing and drying. On the other hand, 30% and 15% contraction of wale direction occurred in orderly float and links & links stitches, respectively. Machine dried knits have a higher shrinkage rate than air-dried knits, but the drying method did not affect to the direction of contraction. In conclusion, variations of knit, tuck, and float stitches affect knit construction and dimensional stability from shrinkage in wet cleaning and drying of wool knitted fabrics.

• The Korea Journal of Herbology
• /
• v.27 no.6
• /
• pp.139-145
• /
• 2012

Objectives : This study aimed to investigate value differences among Gastrodiae Rhizoma samples(GM, GC, G1, G2 and G3) in various characteristics as well as to provide basic guideline for various processes such as steaming and drying of Gastrodiae Rhizoma. Methods : Gastrodiae Rhizoma were steamed and dried at different temperature and times. They were divided into samples (GM; cultivated, steamed and dried in Muju, GC; cultivated and dried in China, G1; steamed and dried at $55^{\circ}C$ for 60 hours, G2; steamed and dried at $55^{\circ}C$ for 120 hours, G3; steamed and dried at $70^{\circ}C$ for 120 hours) for experiment. They were extracted using water, freeze dried and powdered to analyze gastrodin content, antioxidant activity and sensory evaluation. Results : Proximate composition and the amount of free sugars of Gastrodiae Rhizoma had a little bit differences. Phenolic and flavonoid content of samples were increased by increasing drying temperature and times. Gastrodin content had different values by drying method and G3 was the highest in comparison with others. Increasing drying times led to a increasing in radical and nitrate scavenging activity in samples. Regarding to sensory evaluation, G3 was selected as the best sample according to its highest hedonic score mean (6.11/7) among all samples for appearance, color, flavor, overall acceptability. Conclusions : The results indicated that G3 sample was effective in views of antioxidant activity, gastrodin content and sensory characteristics. Moreover, Gastrodiae Rhizoma cultivated in Korea were investigated with higher antioxidant activity, gastrodin content and sensory characteristics than those cultivated in China.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.16 no.1
• /
• pp.3263-3291
• /
• 1974

Experimental work of grain bin was carried out to develop the methods of natural air in-bin drying and storage. The method is considered to be more economical, labour saving, and an effective countermeasure to grain loss. To examine the possibility of farm use of the grain bin and to analyze the related factors concerned with in-bin grain drying and storage, ambient air conditions (especially the change of air temperature and relative humidity) and grain quality during drying and storage periods were investigated. A laboratory model bin was constructed to investigate the effect of different forced air conditions on the drying characteristics of rice. In addition, a grain bin with 2.2m diameter and 1.8m height, considered to be the optimum size for the average Korean farm, was constructed and tested to examine the drying and storing characteristics of rice. The weather data analyzed in this study was the nine-year (from 1964 to 1972) record of air temperature and relative humidity in the Suweon area, and the thirty-year (from 1931 to 1960) record of pentad normal relative humidity and air temperature in the Seoul area. From the results of the weather data analyses, the adequate air delivery hours (which was arbitrary defined as the condition to give less than 75% relative humidity) to dry the rice during October were about nine hours (from approximately 10 A.M. to 7 P.M, ) a day, in which the average air temperature was about 15.9$^{\circ}C$ and average relative humidity was 66%. The occurence of days having three hours of such conditions was 1, 2, and 1-day within the 1st, 2nd add last 10-day periods for the month of October, respectively. Therefore, it may be considered that the weather condition in October was satisfactory for the forced natural air drying. The results of the laboratory model bin test were analyzed to obtain the drying curve and drying rate for different drying stages and grain layers in the bin corresponding to various conditions of forced natural air. A drying experiment with a prototype grain bin showed that an approximate 5 percent grain moisture gradient through a 1.6 meter grain deposit was observed after 80 hours of intermittent drying, giving an over dried zone in the lower grain layers and an extremely high grain moisture zone in the upper layers. This indicates that an effective measure should be taken to reduce this high moisture gradient. In order to investigate the drying characteristics of bulk grain in a layerturning operation a grain bin test was performed. This showed a significant improvement of uniform drying. In this test, approximate 107 hours were required to dry a depth of 1.6 meter of grain from an initial moisture content of 22.2 percent to a moisture content of 16.7 percent using an air delivery rate of 2.8 cubic meter per a minute per every cubic meter of grain. This resulted in a 2 percent moisture gradient from the top to the bottom of the bin. During storage period, till the end of June the average temperature of grain was 2~3$^{\circ}C$ higher than ambient air temperature. But during July when the grain moisture content went up slightly (less than 1 percent), the average temperature of the grain also increased to 3~5$^{\circ}C$ higher than ambient air temperature. It is therefore recommended that for safe grain storage, grain should not be stored in sheet metal bins after mid May. From the above results, in-bin rice drying and storage can be used effectively on Korean farms. It is strongly recommended that the use of grain-bin system should be implemented for farm use to improve farm drying and storage of rice.

• Food Science and Preservation
• /
• v.17 no.4
• /
• pp.478-486
• /
• 2010

The qualities of ginger prepared by an MPD (molecular press dehydration) method using maltodextrin, or dried using reused dehydration liquid, or prepared by freeze-drying or hot-air drying, were compared in terms of approximate overall composition, color, water absorption index, water solubility index, total sugar level, reducing sugar concentration, antioxidant activity, and gingerol content. The approximate composition of ginger prepared by the MPD method was lower in overall biochemical content than were those of gingers prepared using other methods. Ginger prepared by the MPD method retained the original ginger color. The water absorption and solubility index of ginger prepared by the MPD method (using maltodextrin) were better than those of gingers dried using other methods. The total sugar content did not change noticeably upon processing. The reducing sugar content of ginger prepared by hot-air drying was low. The antioxidant activity of ginger prepared by the MPD method was higher than that of freeze-dried and hot air-dried ginger samples, with values lower than those of BHA (3(2)-t-Butyl-4-hydroxyanisole) and BHT (2,6-Di-tert-butyl-4-methylphenol). The gingerol content of ginger prepared by the freeze-drying method was higher than that of gingers prepared by other methods. However, ginger constituents were present in the dehydration liquid used in the MPD method. The results indicate that both the MPD method (using maltodextrin) and the use of reused dehydration liquid are efficient methods by which ginger can be dried.

• Journal of Korean Medicine Rehabilitation
• /
• v.27 no.1
• /
• pp.19-25
• /
• 2017

Objectives Eucommiae cortex is one of the frequently used herbs for musculoskeletal disorders, with well-known anti-inflammatory effect. Meanwhile, powdered form of herbal drugs is more advantageous than decoction form, in that storing and taking is more convenient. Thus, the authors aimed to investigate whether the drying method affects the index compound level and anti-inflammatory effect of eucommiae cortex water extract. Methods Eucommiae cortex was extracted in distilled water at $100^{\circ}C$ for 3 hours, filtered, and then evaporated under vacuum. One half of the sample was freeze-dried at $-80^{\circ}C$. Another half of the sample was added with dextrin and then spray-dried at $180^{\circ}C$. To assess the possible change in index compound content, pinoresinol diglucoside was selected as the index marker. The content level of the index compound in various extract sample was quantified through high performance liquid chromatography. In addition, iNOS assay in LPS-induced RAW 264.7 cells was adopted to determine the anti-inflammatory effect of various extract samples. Furthermore, MTT assay was performed to confirm that the result of iNOS assay was not due to cytotoxicity. Results There was no significance difference in index compound content between extract samples obtained through two different drying methods. Anti-inflammatory activity of extract samples were similar at the matching concentration, regardless of the drying methods. Extract samples did not show any significant cytotoxicity. Conclusions Extract samples of eucommiae cortex were obtained through freeze-drying and spray-drying. Neither change in index compound content nor difference in anti-inflammatory activity was observed between drying methods.

• Journal of Pharmacopuncture
• /
• v.11 no.2
• /
• pp.87-95
• /
• 2008

Objectives The aim of this experiment is to provide an differentiation of ginseng, red ginseng, cultivated wild ginseng(CWG), and red wild ginseng(RWG) through component analysis using HPLC(High Performance Liquid Chromatography, hereafter HPLC). Methods Comparative analyses of ginsenoside $Rg_3$, ginsenoside $Rh_2$, and ginsenosides $Rb_1$ and $Rg_1$ of various ginsengs were conducted using HPLC. Results 1. CWG was relatively heat-resistant and showed slow change in color during the process of steaming and drying, compared to cultivated ginseng. 2. Ginsenoside $Rg_3$ was not detected in cultivated ginseng and CWG, whereas it was high in red ginseng and RWG. Ginsenoside $Rg_3$ was more generated in red ginseng than in RWG. 3. Ginsenoside $Rh_2$ appreared during steaming and drying of cultivated ginseng, whereas it was more increased during steaming and drying of CWG. 4. Ginsenoside $Rg_1$ content was more increased during steaming and drying of cultivated ginseng, whereas it was more decreased during steaming and drying of CWG. 5. Ginsenoside $Rb_1$ content was increased about 500% during steaming and drying of cultivated ginseng, whereas it was increased about 30% during steaming and drying of CWG, indicating that ginsenoside $Rb_1$ was more generated in red ginseng than in RWG. 6. Ginsenoside $Rg_3$ content was higher, whereas ginsenoside $Rg_1$ content was lower in 11th RWG than in 9th RWG, indicating that ginsenoside $Rg_3$ content was increased and $Rg_1$ content was decreased as steaming and drying continued to proceed. Ginsenoside $Rh_2$ and $Rb_1$ contents began to be increased, followed by decreased after 9th steaming and drying process. Conclusions Above experiment data can be an important indicator for the dentification of ginseng, red ginseng, CWG, and RWG. And the following studies will be need for making good product using CWG.