• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.126-131
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• 2013

BGsome coating on the surface of illite powder was attempted to impart skin affinity and improve various characteristics of the powder for makeup cosmetics. BGsome is a type of hydrated liquid crystalline vesicles prepared by the hydration of 1,3-butylene glycol (BG) dissolved lecithin. BGsome droplets were coated through wet process and the coated powders were analyzed by TGA, SEM, and particle size measurements. Effect of BGsome coating on the physical properties, such as flow-ability, dispersibility, spreadability, and adhesion, were examined. The repose angle of BGsome-coated illite was decreased, which means that BGsome coating improves the flowability of the powder. Dispersibility, spreadability, and adhesion of the coated illite were also improved remarkably. The result of adhesion tests showed that the BGsome-coated illite was evenly adhered onto artificial leather surface with almost no lumps. The flowability, dispersibility, spreadability and adhesion of face powders containing the BGsome-coated illite were also improved.

• Journal of Korea Water Resources Association
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• v.43 no.10
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• pp.921-932
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• 2010

In this study, the adjustment processes of the disturbed channels by sand or gravel mining were investigated by a two dimensional numerical model in the generalized coordinate system. As a numerical scheme, the CIP (cubic interpolated pseudoparticle method) method was used to calculate the advection term in the flow field and central difference method was used to the diffusion term in it. The pit of the channel was partially filled with sediment at the toe of the pit upstream. As time increased, the headcut erosion upstream in the pit was decreased due to the sediment inflow. The almost inflow sediment upstream was trapped into the pit and the sediment deposit wedge migrated downstream in the pit with the steep submerged angle of repose. The numerical model was reproduced well the evolution processes of the channel. The mining pit migrated with speed as the channel was steep, and the numerical results were in overall agreement with the experimental results.

• Journal of Korean Society of Forest Science
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• v.23 no.1
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• pp.29-33
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• 1974

U-Reuk, a laureate musician in the days of King Jin-Heung, Silla Dynasty, built the Eui Rim Reservoir about 1,400 years ago. This was one of the oldest man-made reservoir. The embankment of the reservoir collapsed by the clumsy artificial drainage on August 19, 1972 when the heavy rainfall of 462 mm/day caused a dangerous overflow of the reservoir. The result of the study on the mystic ancient embankment techniques are as follows: 1. Sandy loam derived from the weathering of granite which is the most widely distributed rock type in the area, was used in the embankment. Large size logs (embankment core) of 30-50 cm in diameter were buried lengthwise along the embankment. 2. The six stocks of Pinus densiflora, 3 stocks of Quercus acutissima, 1 stock of Quercus variabilis and 1 stock of Popolus maximowiczii, altogether 11 stocks are identified. Forest types in the nearby area during the days of the reservoir construction seem to be includde a considerable number of Pinus densiflora, Quercus and Populus species. 3. The angle of repose of the earth materials is taken into account during the embankment. On top of the embankment double layers of clay (20-30 cm indepth) were spread and consolidated. Layer of litter of 20-40 cm in deep covered on the clay layer of the embankment completely, and another layer of clay was consolidated over the litter. Finally, a layer of stones of 10-30 cm in diameter and clay (yellow soil layer) toped the embankment. 4. At the lower part of the embankment clay layer was thicker and became thinner as it goes upwards. At every layer, soil was consolidated and burned. When embankment was completed, it was covered evenly with heavy clay, and finally it was topped with general soil. 5. The heavy clay layer on the inner slope of the embankment showed gray phenomena and litter remained raw humus layer. The clay layer functioned as rubber in the water, and raw humus layer prevented water from seepages. Thus, the embankment was solidly built in this way. 6. The ancient embankment techniques used soils conveyed from nearby area taking the angle of repose into account. Once embankment was completed, clay and litter layers were added to have a plasticity and to withstand the water pressure. 7. It is an excellent technique that the reservoir was constructed with least labor for maximum effects while the recent embankment techniques requires a large amount of labor.

• Food Science and Preservation
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• v.22 no.5
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• pp.652-659
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• 2015

The physical properties of wheat kernels were determined as a function of moisture content to optimize the design of equipment for post-harvest management. Several properties, including bulk density, dynamic repose angle, one thousand-kernel weight, specific gravity, length, width, thickness, and area of two wheat cultivars (Baekjjung: B and Jogyeong: J ), were studied in the moisture range from approximately 9% to 30% wet basis. As moisture increased, length increased linearly from 6.42 to 7.20 mm (B) and 8.71 to 9.15 mm (J), width increased from 2.90 to 3.49 mm (B) and 4.12 to 4.43 mm (J), thickness from 2.94 to 3.20 mm (B) and 3.29 to 3.63 mm (J), and area from 14.13 to $19.44mm^2$ (B) and 27.75 to $31.25mm^2$ (J). Additionally, the dynamic repose angle and one thousand-kernel weight increased linearly from $46.3^{\circ}$ to $54.0^{\circ}$ (B) and $46.3^{\circ}$ to $54.5^{\circ}$ (J) and from 32.26 to 41.51 g (B) and 45.30 to 63.07 g (J), respectively, as the moisture content increased. Based on the experimental measurements, only the bulk density and specific gravity decreased from 754.0 to $664.1kgm^{-3}$ (B) and 776.1 to $660.0kgm^{-3}$ (J) and from 1.2950 to 1.2265 (B) and 1.3379 to 1.2671 (J), respectively, as moisture content increased.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.46-52
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• 2017

Sediment exchange in river has been affected by artificial changes such as dredging and abnormal climate changes like intense rainfall. Over last decades in Korea, there were many constructions, restoration or rehabilitation in rivers. Therefore, deposition and erosion become more actively occurred than before, which may threaten the river safety such as flood defense. For safety's sake, the dredging of river bed, which is considered as the most typical measure, has been increased to extend hydraulic conveyance compared with previous conditions. However, since it might change the sediment mechanism, there would be another risk at which unexpected side effects such as headward erosion could be occurred. Particularly, sedimentation at abrupt expansion region is able to lead to hydraulic characteristics like water elevation in the upstream region in the beginning of dredging, which, however, has been barely studied in this field. Therefore in this study, the relationship between sediment mechanism at dredging section and hydraulic characteristics in upstream region were presented through numerical simulations in the idealized abruptly widen channel using Delft3D. The ideal channel of 2,000 m length with each side angle of 45 degrees at abruptly widen expansion region was employed to consider the sediment angle of repose. The sensitivity analysis was performed on the dimensionless factors consisted of upstream and downstream depths($h_u$, $h_d$), width($w_u$, $w_d$), water level(H), flow rate(Q) and discharge of sediment($Q_s$). And the sedimentation amount at dredging and the upstream hydraulic characteristics were investigated through that analysis. It showed that $h_d/h_u$, $H/h_u$ and $w_d/w_u$ were more influential in sequence of effect on sedimentation amount, while $h_d/h_u$, $w_d/w_u$ and $H/h_u$ on upstream region. It means that $h_d/h_u$ was revealed as the most significant factors on sedimentation, also it would most highly affect the rising of water level upstream.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.421-426
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• 2013

We evaluated physical properties such as density, compressive characteristics, irrecoverable work, and stress relaxation of red pepper powder with different particle sizes. The particle sizes showed a normal distribution in size, with a particle size of $150{\sim}600{\mu}m$ accounting for 70.95% of the particles in the Hanbando cultivar and 82.21% in the Cheongyang cultivar. Loose bulk density ranged between 0.34 and $0.45g/cm^3$, while tapped bulk density ranged between 0.43 and $0.56g/cm^3$. The Hausner ratio was highest (1.531) at a particle size below $150{\mu}m$ in the Cheongyang cultivar. The compressibility and compression ratios were 0.001351~0.004383 and 1.0062~1.0265, respectively. Irrecoverable work ranged between 69.16% and 90.24%. The $K_2$ value and stress relaxation characteristics were greatest (1.74 and 44.92%, respectively) at particle sizes of $300{\sim}425{\mu}m$ in the Cheongyang cultivar. The dynamic angle of repose was $32.84-49.84^{\circ}$. Overall, particle sizes below $150{\mu}m$ had the highest compactibility, cohesiveness, and transformation.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.101-109
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• 2022

This study describes the results of model experiment to analyze the effect of backfill material types on the behavior of underground facility. In the model experiment, backfill materials around the existing underground facility were applied with soil (Jumunjin standard sand) and CLSM. The displacement of underground facility was analyzed for each excavation stage considering the separation distance between the excavation surface and the backfill area based on the experimental results. When soil was applied as a backfill material, the soil on the back of the excavation surface collapsed by excavation and formed an angle of repose, and the process of slope stability was repeated at each excavation stage. In addition, the displacement of underground facility began to occur in the excavation stage that the failure line of soil passes the installation location of the underground facility. When CLSM was applied as a backfill material, there was almost no horizontal and vertical displacement of the ground regardless of the separation distance from the excavation surface even when excavation proceeded to the backfill depth. Therefore, this result showed that it can have a resistance effect against the lateral earth pressure generated and the collapse of the original ground by adjacent excavation, if a backfill material with high stiffness such as CLSM is applied.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1064-1071
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• 2015

Viscous fermented red ginseng extracts were dried and coated using a fluidized bed coater to increase convenience and consumer acceptance. The methods for making spherical granules of fermented red ginseng extracts with increasing convenience were established by using indigestible dextrin. Spherical granules of fermented red ginseng extracts with increasing convenience were made by mixing indigestible dextrin at 40% (40% IDD), 50% (50% IDD), and 60% (60% IDD) versus the soluble solid content of fermented red ginseng extracts. Spherical granules of fermented red ginseng extracts showed less angle of repose than powder of fermented red ginseng extracts. This means that spherical granules of fermented red ginseng extracts had good fluency with increased convenience. The more indigestible dextrin showed higher yields. Although 50% IDD showed less yield than 60% IDD, 50% IDD was the best mixing ratio for making spherical granules of fermented red ginseng extracts, as fermented red ginseng extracts is known as a healthy food. The optimized operation conditions of the fluidized bed coater for making 50% IDD were feeding rate 0.54 mL/min, atomization air pressure 2.15 bar, and product temperature $83.03^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.970-974
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• 2012

Prunus mume is said to aid in the recovery of fatigue and improvement of liver and stomach functions. To obtain the best benefits of the whole fruit, fresh green Prunus mume was de-seeded and the fruit pulp was vacuum dried. The vacuum-dried pulp was powdered and sieved through a 250 ${\mu}m$ sieve. Then the sieved green Prunus mume powder (GPP) was granulated with water (GPPGW) and with Prunus mume extract (GPPGE) with a fluid bed coater. The physicochemical and sensory properties of GPP, GPPGW, and GPPGE were then evaluated. As a result, the water dispersibility (dispersible time) of GPP, GPPGW, and GPPGE was 21.19 sec, 6.46 sec, and 4.85 sec, respectively. The powder fluency (angle of repose) of GPP, GPPGW, and GPPGE was $11.25^{\circ}$, $8.65^{\circ}$, and $9.52^{\circ}$, respectively. The overall consumer acceptance of GPP, GPPGW, and GPPGE was 3.50, 4.62 and 5.00, respectively. Inconclusion, Prunus mume can be used as granulated whole fruit pulp with good powder fluency and dispersibility.

• Journal of Korea Water Resources Association
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• v.43 no.7
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• pp.657-666
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• 2010

The adjustment processes of mining pits in the disturbed channels by sand or gravel mining were investigated by laboratory experiments in this study. The pit migrated with speed when the river bed was steep. The pit migrated slow and steady when the pit was filling with sand, but the pit migrated with speed after the filling processes was finished. The submerged angle of repose in the pit was nearly constant during the pit was filling. The pit was filled with sand with speed as the channel slope was increased. It took time for the pit to be filled with sand as the pit dimension was increased. This meant that the disturbed channels by sand or gravel mining to adjust the new environment was dependent on the slope of the channels and the dimension of the pits. The dimensionless pit length was short and the dimensionless pit depth was shallow as the time was increased. The dimensionless pit depth was shallow, but the dimensionless pit migration speed was increased as the dimensionless shear velocity and the migration speed of the pit were increased. The dimensionless pit depth was increased with the dimensionless bar migration speed. The shape of the pit was deformed and migrated downstream in accordance with the location and shape of the biased bar front which was developed upstream.