• The KSFM Journal of Fluid Machinery
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• v.11 no.1
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• pp.40-45
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• 2008

This paper proposes a tube pump composed of small-sized cams and followers for an implantable intrathecal drug infusion device. Each followers is driven by a cam and liquid is discharged by a sequential reciprocal motion of the followers. The advantage of this structure is that it allows the pump to be clean and valveless. To design a small-sized, low power pump some analysis were performed to determine the design parameters of the cam, follower and the tube. To verify the feasibility of the experiment, a prototype was manufactured and its operating characteristics were investigated. Experimental results were in accordance with the expected results obtained from analysis.

• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.69-76
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• 2019

In this study, resin flow analysis of resin transfer moulding (RTM) method was performed for mould design of composite structure. The target composite structure was a tank used for fluid storage. Natural c fiber composite was adopted for composite structural design of the fluid storage tank. RTM was adopted for manufacturing of the tank using natural fiber composites. Resin flow analysis was performed to find the proper RTM conditions of the tank. The resin flow analysis was performed using the commercial FEM flow simulation software. After repeated analysis while changing the location of resin inlet and outlet, the proper resin filling time and pattern were found.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.1
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• pp.68-71
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• 2005

• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.70-76
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• 2005

It is expected that use of groundwater wells for contaminated groundwater remediation, artificial groundwater recharge and geothermal heat pump systems is increasing in the future in Korea. Some practical confusions may be produced due to lack of regulations related to permits and registrations of these types of wells. This short note is intended to draw attention of relevant professionals by shortly introducing some relevant code of state regulations in Missouri, USA.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1990.06a
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• pp.58-72
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• 1990

유체 윤활 이론에 의한 저어널 베어링의 해석은 그 적용 버위가 넓기 때문에 다양하게 연구되어왔다. 근래에는 열적 효과의 중요성 때문에, 윤활유의 점도와 온도와의 관계, 윤활유 주입홈에서의 윤활유 혼합현상, Cavitation현상, 고속에서 윤활유의 난류현상, 윤활유 주입구의 위치 그리고 경사진 베어링 축이 유막에 미치는 영향 등 다양한 연구가 활발히 진행되고 있다. 본 연구에서는 반원주형 윤활홈을 갖는 저어널 베어링의 주입 윤활유의 열효과가 베어링 부하량과 마찰에 미치는 영향 등을 고찰하였고, 본 연구를 수행하기 위해, 베어링 Bush와 Shfft벽에서 여러가지 열전달 겅계 조건을 가정한 가운데 Reynolds 방정식을 Energy 방정식과 동시에 수치해석적으로 풀었다. 수치해석 방법은 FDM(Finite Difference Method) 중 SOR(Successive Over-Relaxation)Technigue을 이용하였다. 또한 윤활유 점도와 온도의 관계는 지수함수(Exponential Function) 형태로 취했다. 주입 윤활유 온도와 압력 그리고 윤활홈의 형태 등을 변화시켜가며 베어링 성능에 미치는 영향을 조사하였다.

• Analytical Science and Technology
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• v.9 no.1
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• pp.35-42
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• 1996

A rapid analytical method based on capillary electrophoresis is described for the determination of trace anions in high-purity chemicals which is used to prevent corrosion demage in nuclear power plants. Separations are carried out at 20kV using trimethylsilane-coated fused-silica capillary ($70cm{\times}50$ or $75{\mu}m$ i.d.) with the electrolyte of 5mM Chromate(pH=8). Detection was achieved using on-column indirect photometry at 254nm. The simultaneous analysis of inorganic anions, chloride, nitrate, sulfate, azide and phosphate was performed using methods of hydrodynamic(>1ppm) and / or electrokinetic(<1ppm) injection. The results of studies on the coexisting anions on analyte ions shows that peak responses of analyte in hydrodynamic injection is constant without effect of coexisting anions, but those of analysis in electrokinetic injection is strongly dependant upon the kind of coexisting anions and its ionic mobility. The analyte enrichment rate, hence peak response, is positive relationship with the resistance of the sample solution. Thus, appropriate measures, such as standard addition or internal standard technique, must be used to account for differences in conductance of standard and sample solutions.

• 한국해양학회지
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• v.28 no.1
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• pp.17-23
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• 1993

A right cylindrical tank with sloping bottom and top (${\beta}-effect$) is filled with two-layered fluid and is put on the rotating table. External fluid of same density as the lower-layer fluid is continuously injected to drive the lower-layer current. By minimizing the interfacial stress between two layers the motion in the lower-layer deformed the shape of interface such that the upper-layer adjust itself to the variations of the interface in terms of its direction of flow patterns .The most significant parameter is the internal Froude Number($F_1$) and when $F_1$ is greater than 6 two-cellular circulation of the upper-layer changes its direction, there by creates a separation of Western boundary current. The separation position moves to the most northward when $F_1$ equals to 6.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.433-445
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• 2021

Plasma blasting by high voltage arc discharge were performed in laboratory-scale soil samples to investigate the fluid penetration efficiency. A plasma blasting device with a large-capacity capacitor and columnar soil samples with a diameter of 80 cm and a height of 60 cm were prepared. Columnar soil samples consist of seven A-samples mixed with sand and silt by ratio of 7:3 and three B-samples by ratio of 9:1. When fluid was injected into A-sample by pressure without plasma blasting, fluid penetrated into soil only near around the borehole, and penetration area ratio was less than 5%. Fluid was injected by plasma blasting with three different discharge energies of 1 kJ, 4 kJ and 9 kJ. When plasma blasting was performed once in the A-samples, penetration area ratios of the fluid were 16-25%. Penetration area ratios were 30-48% when blastings were executed five times consecutively. The largest penetration area by plasma blasting was 9.6 times larger than that by fluid injection by pressure. This indicates that the higher discharge energy of plasma blasting and the more numbers of blasting are, the larger are fluid penetration areas. When five consecutive plasma blasting were carried out in B-sample, fluid penetration area ratios were 33-59%. Penetration areas into B-samples were 1.1-1.4 times larger than those in A-samples when test conditions were the same, indicating that the higher permeability of soil is, the larger is fluid penetration area. The fluid penetration radius was calculated to figure out fluid penetration volume. When the fluid was injected by pressure, the penetration radius was 9 cm. Whereas, the penetration radius was 27-30 cm when blasting were performed 5 times with energy of 9 kJ. The radius increased up to 333% by plasma blasting. All these results indicate that cleaning agent penetrates further and remediation efficiency of contaminated soil will be improved if plasma blasting technology is applied to in situ cleaning of contaminated soil with low permeability.

• Membrane Journal
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• v.25 no.3
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• pp.268-275
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• 2015

Effects of aeration intensity on local fouling were investigated in submerged membrane modules. Higher liquid velocities were observed at the section with the lower fiber packing density. The liquid velocity is increased with increasing the gas-liquid injection factor. The high shear stress coincided with the high liquid velocity. The shear stress increases with the increasing of gas-liquid injection factor and the liquid velocity improves with the increasing of gas-liquid injection factor. Irreversible fouling resistance ($R_{ir}$) of the fiber position is significant in a local region of high suction pressure near the suction point of the fiber (position 1). The ratio of $R_{ir}/R_m$ and $R_{ir}/R_r$ of position 1 was highest compared to the position 2 and 3. Irreversible fouling resistances results confirmed the preferential deposition of foulants near the suction part of the fiber where the local suction pressure is the highest and correspondingly, more particles are accumulated to the membrane surface. The effects of local fouling along the fiber length are significant factors to optimize the design of submerged modules.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1546-1547
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• 2007

휴대용 면역진단 시스템을 구현하기 위하여 설계된 공기주입기로 구동되는 랩온어칩 내의 유체 유동을 컴퓨터 시뮬레이션을 통하여 해석하고, 문제점을 보완할 수 있는 구조로 랩온어칩을 재설계하였다. 공기주입기에서 흘러나오는 공기를 이용해 완충액 저장고 내에 있는 완충액을 토출시킬 때 다량의 기포가 발생함을 시뮬레이션 결과를 통해 알 수 있었다. 완충액 저장고의 내부에 계단형 구조를 삽입함으로서 완충액 이송 시 형성되는 기포를 상당히 억제할 수 있었다. 또한 계단형 구조는 유선을 역행 방지판 쪽으로 분산시켜 역행 방지판의 효율을 높일 것이다.