• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.146-151
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• 2007

Resistant starch (RS) content, paste viscosity, water solubility and absorption index, bulk density, color, compression force, and bowl life of Goami flakes manufactured by extrusion process were determined to evaluate Goami (high fiber rice) as a food material. Various extrusion process conditions included barrel temperature (90, 110, $130^{\circ}C$) and moisture content (50, 55%). RS content in the extruded pellet and defatted flake ranged from $8.00{\sim}8.56%$ and $6.57{\sim}9.53%$ respectively. RS content increased as moisture increased from 50% to 55%. Peak viscosity, trough viscosity, final viscosity, and setback viscosity of the extruded pellet and defatted flake decreased with steeping for 1 hr, and the breakdown viscosity significantly increased. The water solubility and absorption index increased in the flake compared to Goami and extruded pellet. The water solubility index of the extruded pellet was lower than that of Goami, while its water absorption index was higher than Goami. The bulk density of the flake ranged from $0.35{\sim}0.44$ g/mL. The bowl life of the flake was $12.4{\sim}19.4$ min, which was longer than commercial breakfast cereals on the market.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.259-266
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• 2014

Understanding the forest fire patterns is necessary to comprehend the stability of the forest ecosystems. Thus, researchers have suggested the simulation models to mimic the forest fire spread dynamics, which enables us to predict the forest damage in the scenarios that are difficult to be experimentally tested in laboratory scale. However, many of the models have the limitation that many of them did not consider the complicated environmental factors, such as fuel types, wind, and moisture. In this study, we suggested a simple model with the factors, especially, the geomorphological structure of the forest and two types of fuel. The two fuels correspond to susceptible tree and resistant tree with different probabilities of transferring fire. The trees were randomly distributed in simulation space at densities ranging from 0.5 (low) to 1.0 (high). The susceptible tree had higher value of the probability than the resistant tree. Based on the number of burnt trees, we then carried out the sensitivity analysis to quantify how the forest fire patterns are affected by the structure and tree density. We believe that our model can be a useful tool to explore forest fire spreading patterns.

• Wind and Structures
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• v.26 no.6
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• pp.369-382
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• 2018

Tornadoes are vertical swirling air formed because of the existence of layers of air with contrasting features of temperature, wind flow, moisture, and density. Tornadoes induce completely different wind forces than a straight-line (SL) wind. A suitably designed building for an SL wind may fail when exposed to a tornado-wind of the same wind speed. It is necessary to design buildings that are more resistant to tornadoes. In tornado-damaged areas, dome buildings seem to have less damage. As a dome structure is naturally wind resistant, domes have been used in back yards, as single family homes, as in-law quarters, man caves, game rooms, storm shelters, etc. However, little attention has been paid to the tornadic wind interactions with dome buildings. In this work, the tornado forces on a dome are computed using Computational Fluid Dynamics (CFD) for tornadic and SL wind. Then, the interaction of a tornado with a dome and a prism building are compared and analyzed. This work describes the results of the tornado wind effect on dome and prism buildings. The conclusions drawn from this study are illustrated in visualizations. The tornado force coefficients on a dome building are larger than SL wind forces, about 120% more in x- and y-directions and 280% more in z-direction. The tornado maximum pressure coefficients are also higher than SL wind by 150%. The tornado force coefficients on the prism are larger than the forces on the dome, about 100% more in x- and y-directions, and about 180% more in z-direction. The tornado maximum pressure coefficients on prism also are greater those on dome by 150% more. Hence, a dome building has less tornadic load than a prism because of its aerodynamic shape.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.286-286
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• 2017

We conducted to compare the characteristics of rice flours according to the different milling processes. Five rice varieties (Oryza sativa L.) with different amylose content were prepared by wet and dry milling processes. The moisture contents of wet-milled rice flours (WMR) was mostly three-time higher than those of dry-milled flours (DMR). Water absorption index (WAI), water solubility index (WSI) and swelling power (SP) increased in proportion to temperature ($50-90^{\circ}C$). WAI, WSI, SP of DMR showed higher value than those of WMR. Baeokchal (BOC) which is waxy rice cultivar was significantly high level of WSI. Pasting properties of DMR except BOC cultivar resulted in higher peak viscosity, trough viscosity, final viscosity and Setback. The levels of resistant starch in the four cultivars except Dodamssal (DDS) were under 1% irrespective of Milling processes, whereas the resistant starch contents of DMR and WMR in DDS was 9.18 and 6.27, respectively. Damaged starch content of WMR were less than those of DMR, moreover, negative correlation was observed between amylose content and damaged starch of rice cultivars. These results suggest that the properties of rice flour varied depending on the milling methods and varieties, and it could be a reference for selecting the appropriate processing purposes.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.779-787
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• 2018

The objective of this study was to investigate the structural and physicochemical properties of starch by barely cultivars. Hwanggeumchal had a moisture content and ${\beta}$-glucan content of 12.02 and 6.23%, respectively. Hyegang had higher protein contents than those of the other cultivars. As a result of observing the particle size of starch, Hwanggeumchal and Hyegang had smaller particles of starch compared with the other cultivars at 15.7 and $15.9{\mu}m$, respectively. The analysis results on the content of damaged starch showed that Dahan and Hyegang had a damaged starch content of 1.14 and 1.20%, whereas Boseokchal and Hwanggeumchal were 0.76 and 0.49% respectively, showing low waxy cultivars. As for the content of amylose, the results show that Dahan and Hyegang had an amylose content of 37.07 and 37.75%, and Boseokchal and Hwanggeumchal were at 11.22 and 37.75%, respectively. As for the degree of amylopectin polymerization, all four cultivars had the highest degree of polymerization (DP) content of 13 - 24 at more than 54%, whereas the DP content ${\geq}37$ was the lowest at less than 5.35%. The results for the soluble and resistant starch content show that the content of soluble starch ranged from 93.90 to 95.76%, and resistant starch was 0.17 - 0.40%. After analyzing the gelatinization properties of barley starch, the value of the setback was low in Hwanggeumchal and Hyegang; thus, it is considered that the aging process of those cultivars will be slower than that of the others.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.703-712
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• 1998

Physicochemical factors, microbial population size and the properties of the bacterial isolates were estimated to find out the nature of soil ecosystem of Mt. Nam. Samples were obtained from the surface layer of soils on which specific plant community is developed. Average content of moisture and organic matter of the soils were 21.6% and 17.3%, respectively. These values were similar to those of developing forest soils, but were slightly lower than those of climax ecosystem such as Piagol in Mt. Chiri. Chiri. Content of phosphate was higher than those of other forest soils. The population size of soil bacteria ranged from 27.4 to 195.8 ${\times}\;10^5$ CFU/g. duy soil, and the size is somewhat dependent on the moisture and oranic matter content of soils. A large number of bacteria were able to decompose macromolecules such as starch, elastin and gelatin. Bacterial species composition of each soil was comparatively simple. Pseudomonas, Agrobacterium, Flavobacterium and Xanthomonas which are Gram-negative short rods were widely distributed in the forest soils. The endospore forming Bacillus species were also the main constituents of the soil microflroa. Actinomycetes were widely distributed in the forest soils, but the distribution pattern varied in each site. Most of the actinomycetes were also able to decompose organic macromolecules. The rate of resistant actinomycete strains to antibiotics and heavy metals were lower than those from cultivated soils, but higher than those from well-preserved forest soils. Antibiosis pattern of the actinomycete isolates was similiar to the resistance pattern. This means the forest soils of Mt. nam was somewhat interferred by artificial behabiour.

• The Korean Journal of Ecology
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• v.21 no.5_2
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• pp.575-583
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• 1998

Physicochemical factors, microbial population size and the properties of the bacterial isolates were assessed to find out the nature of soil ecosystem of Mt. Paektu. Samples were obtained from the surface layer of soils on which specific plant community is developed. Average content of moisture, organic matter and avaiable phosphate of the soils were 21.6%, 17.3% and 2.48mg/100g, respectively. These values were similar to those of developing forest soils, but were slightly lower than those of climax ecosystem such as Piagol in Mt. Chiri. The population size of soil bacteria ranged from 2.7 to $202.5{\times}10^5$ CFU/g.dry soil, and the size is somewhat dependent on the content of moisture and oranic matter of the forest soil. A large number of bacteria was able to decompose macromolecules such as starch, elastin and gelatin. While the distribution rate of resistant bacteria to antibiotics was high, that to toxic chemicals was low. This means that the competition between microorgani는 predominate over the interference with artificial behaviour such as spread of pesticides in the surveyed region. Bacterial species composition of each soil was comparatively simple. Pseudomonas, Agrobacterium, Flavobacterium and Xanthomonas which are Gram-negative short rods were widely distributed in the forest soils. The endospore forming Bacillus species were also main constituents of the soil microflroa. any one of the strains was not identified as Azospirillum or Micrococcus which are known to be one of major constituents of the forest soil. for the correct identification of isolates chemotaxonomic studies will be proceeded, and the strains are to be stored in the Type collection Center.

• Journal of the Korean Society of Food Culture
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• v.24 no.2
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• pp.191-198
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• 2009

The objective of this study was to investigate the effects of different amounts of pumpkin powder on the quality characteristics of hobakpyeon using physicochemical and sensory properties, as well as on its retrogradation rate during storage. As the amount of pumpkin powder increased, the following effects on the quality characteristics were observed: moisture and amylose contents decreased while protein content increased (p<0.05), and in vitro protein digestibility (IVPD) decreased (p<0.05). Levels of slowly digestible starch and resistant starch fractions increased, while the content of rapidly digestible starch decreased. The starch digestion index and rapidly available glucose content also decreased. Among the physical properties, the L-value decreased while the b-value increased (p<0.05). Texture profile analysis revealed that all textural properties except adhesiveness decreased, and presented significant differences in hardness and chewiness (p<0.05). Sensory properties such as color, flavor, and sweetness increased while others such as wetness and chewiness decreased (p<0.05). Effects on the physicochemical properties during refrigerated storage were also compared between the control and 9% hobakpyeon (9%HP). According to the results, moisture content gradually decreased in the 9%HP compared to the control. Amylose content significantly increased in 9%HP whereas no significant changes were observed in the control. In both types of hobakpyeon, IVSD decreased significantly, showing higher values in 9%HP, whereas mechanical hardness increased, showing lower values in 9%HP. The L-value decreased significantly in the 9%HP whereas no significant changes were observed in the control. In conclusion, the above results suggest that hobakpyeon with low IVSD may be obtained by the addition of 9% pumpkin powder, and also showed that pumpkin powder delayed the rate of retrogradation in 9%HP during storage.

• Journal of the Korean Ceramic Society
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• v.50 no.2
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• pp.127-133
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• 2013

Porcelain with high thermal shock resistance was successfully fabricated by a lithium solution infiltration method with a lithium hydroxide solution. Lithium hydroxide solutions having various lithium concentrations were infiltrated into pre-sintered porcelain bodies. The porcelain sample infiltrated by the 9 wt% lithium solution and heat treated at $1250^{\circ}C$ for 1 h showed a low thermal expansion coefficient of $1.0{\times}10^{-6}/^{\circ}C$ with excellent thermal shock resistance. The highly thermally resistant porcelain had a well-developed ${\beta}$-spodumene phase with the general phases observed in porcelain. Furthermore, the porcelain showed a denser structure of $2.41g/cm^3$ sintering density and excellent whiteness in comparison with commercial thermally resistible porcelains. The lithium hydroxide in the samples readily reacted with moisture, and liquid phase reactants were formed during the fabrication process. In the case of an excess amount of lithium in the sample body, the lithium reactants were forced to the surface and re-crystallized at the surface, leaving large pores beneath the surface. These phenomena resulted in an irregular structure in the surface area and led to cracking in samples subjected to a thermal shock test.

• The Plant Pathology Journal
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• v.27 no.3
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• pp.249-256
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• 2011

Tall fescue (Schedonorus phoenix Scop.) is resistant to abiotic and biotic stresses through a symbiotic relationship with Neotyphodium coenophialum. However, this endophyte has been considered detrimental since it produces toxic alkaloids to animals. It is vital to understand mutuality between these two to maximize positive impact of the endophyte on agri-ecosystem. Little research has been conducted on endophyte transmission mechanism in planta. To provide basic information related to endophyte transmission, an experiment was conducted to examine the effect of endophyte genotype and water stress on endophyte transmission by imposing soil moisture deficits at different stages of panicle development. There was water stress effect on endophyte frequency but not on concentration, whereas endophyte genotype significantly influenced endophyte concentration in pseudostem of tall fescue at boot stage. Reproductive tillers showed greater endophyte frequency and concentration. Endophyte frequency in florets or seeds depended on position within panicle. There was no drought effect on endophyte concentration, but showed the effect of endophyte genotype on endophyte concentration in florets and seeds. Overall endophyte concentration in seeds was higher. From this study, we may conclude that although water stress reduced endophyte frequency in vegetative tiller, water stress does not have effect on endophyte transmission, suggesting that drought is not an important factor controlling the endophyte transmission from plant to seed. Endophyte genotype and seed position in a panicle affected endophyte transmission, indicating that these two factors are involved in endophyte transmission and may determine seed transmission of endophyte in tall fescue.