• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.120-125
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• 2001

The effects of various vaned diffuser configurations, such as throat area ratios and rectangular and conical cross-section shapes. to the performance of a small-size turbo-compressor are studied. Numerical analyses were carried out for the region of diffuser and casing only. The pressure recovery coefficient was calculated to estimate the performance of the diffuser, and then compared with the measured data. Results show that the shapes and the throat area ratios of the diffuser strongly influence on the performance of a turbo-compressor.

• KSTLE International Journal
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• 제4권1호
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• pp.31-36
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• 2003

Sliding and impact/sliding wear test in room temperature air and water were performed to evaluate the effect of spring shapes on the wear mechanism of a fuel rod. The main focus was to quantitatively compare the wear behavior of a fuel rod with different support springs (i.e. two concaves, a convex and a flat shape) using a ratio of wear volume to worn area (De)-The results indicated that the wear volumes at each spring condition were varied with the change of test environment and loading type. However, the relationship between the wear volume and worn area was determined by only spring shape even though the wear tests were carried out at different test conditions. From the above results, the optimized spring shape which has more wear-resistant could be determined using the analysis results of the relation between the variation of De and worn surface observations in each test condition.

• 한국위험물학회지
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• 제6권2호
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• pp.62-67
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• 2018

It is very important to classify explosion hazardous area in order to prevent an accident explosion. In order to prevent such a explosion, the Industrial Safety and Health Standards Rules stipulates the establishment and management of explosion hazards in accordance with the criteria set by the Korean Industrial Standards. This study has investigated the range of the explosion hazardous area according to various hole sizes, pressures, vapor densities, and wind velocities in the outdoor flammable liquid tank using KS C IEC-60079-10-1 $2^{nd}$ Ed.(=IEC CODE) and PHAST. The results show that the explosion hazardous areas by IEC CODE have circle shapes. However, the areas by PHAST show ellipse shapes. The different of the explosion hazardous areas increases with the increase of wind velocity.

• 한국가스학회지
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• 제7권4호
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• pp.53-60
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• 2003

보통 가정이나 건물에서 화재 및 가스에 의한 사고 중에 가스의 폭발에 의한 사고는 폭발과 동시에 발생하는 압력 때문에 발생하는 건물의 붕괴로서 많은 인명피해 및 재산상의 손해를 가져온다. 이와 같은 2차적인 피해를 막기 위해 본 연구에서는 건물의 폭발시 발생하는 개구부의 크기 및 형태에 따른 모델을 선정하여 건물의 체적대비 개구부 면적에 따른 압력변화를 실험을 통하여 개구부의 면적 비를 도출하였으며, 개구부 형태에 따른 압력실험을 통하여 최소의 압력으로 피해을 막을 수 있는 모델을 선정하였다. 이를 이용하여 건물의 설계시 안전율을 고려하여 개구부의 면적 및 형태를 선정함으로써 2차 피해를 예방할 수 있을 것으로 판단된다.

• Journal of Ecology and Environment
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• 제32권1호
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• pp.61-65
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• 2009

We compared two nondestructive methods for leaf area estimation using leaves of 16 common plant species classified into six types depending on leaf shape. Relatively good linear relationships between actual leaf area (LA) and leaf length (L), width (W), or the product of length and width (LW) were found for ordinary leaves with lanceolate, oblanceolate, linear and sagitttate shapes with entire margins, serrate margins, mixed margins with a entire form and shallow lobes, and ordinary incised margins. LA was better correlated with LW than L or W, with $R^2$ > 0.91. However, for deeply incised lobes, LA estimation using LW showed low correlation coefficient values, indicating low accuracy. On the other hand, a method using photographic paper showed a good correlation between estimates of area based on the mass of a cut-out leaf image on a photographic sheet (PW) and actual leaf area for all types of leaf shape. Thus, the PW method for LA estimation can be applied to all shapes of leaf with high accuracy. The PW method takes a little more time and has a higher cost than leaf estimation methods using LW based on leaf dimensions. These results indicate that researchers should choose their nondestructive LA estimation method according to their research goals.

• Wind and Structures
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• 제9권2호
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• pp.147-158
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• 2006

The purpose of this paper is to find a more accurate method to evaluate pedestrian wind by computational fluid dynamics approach. Previous computational fluid dynamics studies of wind environmental problems were mostly performed by simplified models, which only use simple geometric shapes, such as cubes and cylinders, to represent buildings and structures. However, to have more accurate and complete evaluation results, various shapes of blocking objects, such as trees, should also be taken into consideration. The aerodynamic effects of these various shapes of objects can decrease wind velocity and increase turbulence intensity. Previous studies simply omitted the errors generated from these various shapes of blocking objects. Adding real geometrical trees to the numerical models makes the calculating domain of CFD very complicated due to geometry generation and grid meshing problems. In this case the function of Porous Media Condition can solve the problem by adding trees into numerical models without increasing the mesh grids. The comparison results between numerical and wind tunnel model are close if the parameters of porous media condition are well adjusted.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.254-257
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• 1998

The twisting and the bending of extruded product are caused by the shapes of products and by the shapes of die surfaces and by the shapes of die land. Because the elliptical shape and the circular shape of the extruded product have the symmetry line of cross-section area, the twisting and the bending of product has not occurred. But the analysis by the DEFORM-3DTM show that the twisting and the bending of extruded product can be occurred by the twisting of the twisting of the die land and by the curving of the die land. The results by the analysis show that the twisting angle of the extruded procduct increases by the twisting angle of the die land and the curvature of the extruded products increases by the radius of bending of the die land.

• 한국의류학회지
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• 제21권4호
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• pp.689-698
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• 1997

The purpose of this study is to develop the well-fitted brassieres by observing the changes in the breast sizes and shapes, the surface area and the volume of the breast through the arm movements of 3 types (0$^{\circ}$, 90$^{\circ}$ and 180$^{\circ}$) in vertical motion. The subjects are females, who are aged twenties and wearing a brassiere size 70B, In particular, to obtain the measures regarding the surface area and the volume of the breast, replicas are made at each motion. The results of this study are as follows: 1. The changes in the breast sizes and shapes at each motion By increasing the motions of the arm movement, the following measure items are inclined to decrease: Shoulder length, Side neck point~B.P., Front neck point~B.P., Horizontal length of the cup, Upper bust circumference, Bust circumference, Upper bust depth, Bust depth, Under bust depth, Nipple to tipple breadth, Horizontal distance of bust, Bust height, Cup size. By increasing the motions of the arm movement, the following measure items are inclined to increase: Center point of shoulder~B.P., Shoulder point~B.P., Armpit~ lowest point of breast drooping, Upper bust point~B.P., B.P~Under bust point, Under bust line, Width of gap between breast, Vertical distance of Bust. 2. The changes in the surface area and volume of breast at each motion By making the replica to observe changes in the surface area, which are sectioned to 4 parts(area 1 to area 4) , and volume of breast at each motion, the results are as follows: At 0$^{\circ}$ and 90$^{\circ}$, the sizes of each part are ordered as the following: area2> areal> area4> area3. At 180$^{\circ}$, the sizes of each part are ordered as the following: areal> area2> area4> area3. Through these orders, it is found that the upper and inside part of the breast has the inclination to increase so long as the motions of the arm movement increase. Also, the total surface area increases so long as the motions of the arm movement increase. The volume of the breast increase when the surface area of the breast increases. As a result of the F-test on the changes in the each surface areas, the surface area and volume by arm movements, the significant differences among the each surface areas and the surface area are not found.

• 대한의용생체공학회:의공학회지
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• 제39권1호
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• pp.30-35
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• 2018

Conventional drug delivery methods mainly include subcutaneous injection and oral administration. Subcutaneous injection has the advantages of delivering the correct concentration, but it might cause pain and trauma to patients. Although oral administrations do not accompany pain as the subcutaneous injection, unexpected side effects may occur because they undergo digestion process and it is not easy for many drugs to be exposed to targeted sites with proper concentration. While dissolving microneedles have been extensively studied to overcome the limitations of conventional subcutaneous injection, the effects on microneedle shapes for drug release have not been fully explored. In this study, the characteristics of hyaluronic acid microneedles for cone and quadrangular pyramidal shapes were examined by the size, volume, contact surface area, skin permeability, and dissolution rate. As a result, the cone shapes of hyaluronic acid microneedles had high skin permeability, and the quadrangular pyramid of shapes hyaluronic acid microneedles showed a fast dissolution rate, given by the large contact area on the skin. Based on the results, we could confirm that the shape of a dissolving microneedles can affect skin permeability and the drug delivery rate.

• 대한가정학회지
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• 제37권11호
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• pp.49-58
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• 1999

This study is to develop the well-fit brassieres by observing the changes in the breast sizes and shapes, the surface area of the breast through the arm movements of 3 types (0$^{\circ}$ , 90$^{\circ}$ and 180$^{\circ}$) in vortical motion. The 11 elementary girls who are aged 12 participated in this experiment. To obtain the measures regarding the surface area of the breast, replicas are made at each motion. The results of this study are as fellows: 1. The changes in the breast sizes and shapes at each motion By increasing the motions of the arm movement, the following measure items are inclined to decrease: Shoulder length, Upper blast girth, Bust girth, Under bust girth, Upper bust depth, Bust depth, Under bust depth, Nipple to nipple breadth, Horizontal distance of bust, Horizontal length of the cup, Bust height, Cup size. By increasing the motions of the arm movement, the fellowing measure items are inclined to increase: Center point of shoulder~B.p., Shoulder point~B.p., Center point of shoulder~armpit, Upper Bust breadth, Bust breadth, Under bust breadth, Vertical distance of Bust. 2. The changes in the surface area of breast at each motion By making the replica to observe changes in the surface area, which are sectioned to 4 parts(area 1 to area 4), and volume of breast at each motion, the results are as follows: At 0$^{\circ}$and 180$^{\circ}$, the sizes of each part are ordered as the following: area2>area1>area4> area3. At 90$^{\circ}$, the sizes of each part are ordered as the following: area2>area1>area3>area4. Through these orders, it is found that the upper and inside part of the breast huts the inclination to increase so along as the motions of the arm movement increase. Also, the total surface area increases so long as the motions of the arm movement increase. As a reset of the F-test on the changes in the each surface areas, the surface area by arm movements, the significant differences among the each surface areas are found.