본 연구에서는 대면적을 지니는 CDI 모듈의 흐름 향상을 위하여 유체가 들어가는 유입구로부터 면적이 증가하는 직사각형 형태의 유로를 설계하였다. 이를 바탕으로 설계된 모듈 형태에 대해 공급수의 흐름성과 사영역의 유무를 파악하였고 CFD 전산 유체 역학 프로그램을 통해 유로 내의 내부 압력, 유선 그리고 속도 벡터 분포를 분석하였으며 실제 흐름 관측과 CFD 프로그램을 비교 분석하였다. 실험 결과 모든 유속 10, 20, 30 mL/min에서 유로 내 사영역이 거의 발생하지 않았으며 공급수의 흐름성도 일정하게 유지되어 추후 대면적을 가지는 CDI 공정에 적용이 가능할 것이라 판단된다.

LDV(laser Doppler velocimetry) measurements were conducted at a total of four planes at 0.4 speed ratio. The speed ratio of 0.4 is 1600rpm of impeller and 633rpm of turbine speed. Even at the speed ratio 0.4, fluid flow at the gap region between the impeller and turbine and impeller exit was leaving the impeller and flowing up behind the turbine, and flows were affected by the turbine blade as it passed, negatively effecting converter efficiency. In the gap region, fluctuations make a clear sinusoidal trend unclear. The rise and fall of the flow rates in a broad sense, indicate a dependency based on the passage of the turbine blade in front of the impeller passage exit but a sinusoidal trend is not evident from this data.

In this study, the temperature, the absolute humidity, and the turbulent flow characteristics of exhaust air and supply air in the mixer were studied while changing the shape of the mixer of the white smoke reducing heat exchange system. Using Solidworks, the mixer of the white smoke reduction heat exchange system was created by 3-D model. Also, the mixed flow of supply air and exhaust air inside the mixer under the uniform inlet conditions was computed, using the solidworks flow simulation. Two types of improvement models were selected by using a perforated plate and a guide vane as a turbulent mixing flow control method of the mixer. The mean temperature and mean absolute humidity of the mixture were greatly decreased according to the internal shapes of Case 1, 2, and 3. The temperature difference between the inlet and outlet of the mixer Case 3 was 26℃. The exit temperature and absolute humidity reduction rates of Case 3 were 26.2% and 48.1%, respectively, compared with Case 1.

Angiography has excellent advantages to visually observe the internal morphology of the stenosed blood vessel. For OCT(Optical coherence tomography), it is possible to directly provide a reliable two-dimensional cross-sectional information as compared to conventional angiography. In the present study, both velocity and wall shear stress distributions were numerically investigated using stenosed blood vessel models (0%, 25%, 50%, and 75% stenotic expansion rate). The blood vessel geometry was prepared based on the human stenotic aorta from OCT image. Commercially available software (CATIA V5) was used to reconstruct 3D blood vessel for numerial analysis. Pulsatile blood flow boundary condition was applied. The numerical study could help our understanding of the hemodynamic differences in a stenosed blood vessel.

한국 남해안 금호열도 주변 다도해역의 조류특성과 해수순환 구조를 파악하기 위해 대조와 소조시 ADCP bottom tracking을 이 용한 25시간 선박 항주관측을 실시하였다. 대조시 낙조와 창조 방향은 남동-북서이며, 최강유속은 표층 약 40 cm/s이다. 개도주변은 지형적 특성으로 주변해역의 탁월유향과 다르고, 유향·유속의 분산이 크다. 전 구간 표~저층 흐름에 두드러진 경압모드 성분은 없었다. 이는 좁은 수로와 얕은 수심, 빠른 유속으로 지형성와류나 eddy로 인한 연직혼합이 활발했음을 나타낸다. 소조시 조류는 남남동-북북서, 평균유속은 대조의 85 %이다. 탁월유향은 대조보다 우세하지 못하고 지속시간도 짧다. 흐름은 연직방향 유속시어, 수평와류, 비대칭 조류혼합으로 물질의 수평·연직이동이 왕성할 것으로 추정된다. 일평균조류는 개도 서~북서 수로해역이 북서~북동, 금오도 서쪽은 서남서~남남서 방향 최 대 21 cm/s의 흐름이 존재한다. 소리도 서쪽에는 좌선환류나 와류가 형성되었다.

Generally, ceramic tiles for building construction are manufactured by dry forming process using granular powders prepared by spray drying process after mixing and grinding of mineral raw materials. In recent years, as the demand for large ceramic tiles with natural texture has increased, the development of granule powders with high packing ratio and excellent flowability has become more important. In this study, ceramic tile granule powders are coated with hydrophobically treated silica nanoparticles. The effects of hydrophobic silica coating on the flowability of granule powders and the strength of the green body are investigated in detail. Silica nanoparticles are hydrophobically treated with GPTMS(3-glycidoxypropyl trimethoxy silane), which is an epoxy-based silane coupling agent. As the coating concentration increases, the angle of repose and the compressibility decrease. The tap density and flowability index increase after silica coating treatment. These results indicate that hydrophobic treatment can improve the flowability of the granular powder, and prevent cracking of green body at high pressure molding.

The flow characteristics around the vertical wall with the flap were visualized in the water channel using PIV. And the effect of flap angle change was investigated to see how quickly the spreading can be prevented and confined if oil spill occurs at sea. As a result, the fluid in the front of the vertical wall flows constantly, Nearing a boundary layer on the vertical wall, and a flow separation phenomenon occurs. Thereafter, flow loss or depth loss to the bottom of the vertical wall was confirmed. Also, it was observed that irregular reverse circulation flow occurred due to flap angle change and pressure gradient at the back of vertical wall. In this study, it was analyzed that it is most effective at 20 degrees angle. In the future, it is necessary to confine the flow characteristics of PIV and CFD by assuming that there is a double vertical wall in which oil having a lower specific gravity than water is trapped in the oil fence.

범죄는 인적 또는 물적으로 피해를 일으키기 때문에 범죄가 발생한 이후에 조치를 취하는 것보다는 사전에 범죄를 예방하는 것이 중요하다. 또한, 범죄를 예방하기 위해서는 범죄발생에 취약한 지역을 추출해야 한다. 이에 본 연구에서는 범죄발생 위치정보 를 제공하지 않는 국내의 상황을 고려하여 실제 범죄정보를 직접적으로 사용하지 않으면서 시·공간적 특성을 고려한 범죄취약지역을 추출하는 연구를 수행하였다. 공간적인 특성정보는 연속수치지도에서 추출한 도로폭, 도로교차점, 도로교차각, 포장재질, 도로에 인접한 건물의 종류를 이용하여 범죄에 취약한 위험도로를 추출하였다. 또한 시간적인 특성정보는 점 형태로 제공되는 유동인구 데이터를 커널밀도 분석하여 추출하였다. 시·공간적인 분석을 위하여 두 가지 특성정보를 중첩 분석하여 범죄취약지역을 추출하였다. 취약지역을 검증하기 위해 다음포탈에서 제공하는 로드뷰 영상을 확인한 결과 추출된 취약지역이 노후화된 단독주택이 많고 도로주변이 잘 정비되지 않은 지역임을 알 수 있었다.

In the modern industrial period, the introduction of mass production was most important progress in civilization. Die-casting process is one of main methods for mass production in the modern industry. The aluminum die-casting in the mold filling process is very complicated where flow momentum is the high velocity of the liquid metal. Actually, it is almost impossible in complex parts exactly to figure the mold filling performance out with the experimental knowledge. The aluminum die-castings are important processes in the automotive industry to produce the lightweight automobile bodies. Due to this condition, the simulation is going to be more critical role in the design procedure. Simulation can give the best solution of a casting system and also enhance the casting quality. The cost and time savings of the casting layout design are the most advantage of Computer Aided Engineering (CAE).. Generally, the relations of casting conditions such as injection system, gate system, and cooling system should be considered when designing the casting layout. Due to the various relative matters of the above conditions, product defects such as defect extent and location are significantly difference. In this research by using the simulation software (AnyCasting), CAE simulation was conducted with three layout designs to find out the best alternative for the casting layout design of an automotive Oil Pan_BJ3E. In order to apply the simulation results into the production die-casting mold, they were analyzed and compared carefully. Internal porosities which are caused by air entrapments during the filling process were predicted and also the results of three models were compared with the modifications of the gate system and overflows. Internal porosities which are occurred during the solidification process are predicted with the solidification analysis. And also the results of the modified gate system are compared.

This study was successfully achieved out the optimized system for dispersing and mixing condition of resin liquid. The flow analysis was simulated according to the shape of the impeller and the stirring tank using ANSYS software and optimized in advanced design. As a result, it was confirmed that the shape and double number of the impeller on the flow field are influenced better effects in a range of mixing and diffusion areas comparing to single number of impeller. It was considered that stirring was performed more quickly and efficiently under the condition of double numbers and saw tooth type impeller. This result can be applied practically for the mixing tank in the industrial application and avaliable used to make a new system for painting equipment.