• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.341-345
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• 2005

Since it is troublesome to estimate adequate flow rates in four sections of SMB chromatography, a systematic determination of the flow rates has been suggested by using ketoprofen as a model chiral enantiomer. S-ketoprofen. less retained species, was separated from raffinate stream and the variation in its purity was dependent on the changes of the flow rate of section 4 ($Q_4$), the raffinate flow rate ($Q_{raf}$), and the feed flow rate ($Q_{feed}$) under a fixed switch­ing time t$^{\ast}$. When one parameter was changed at the given experimental condition, purities of product were changed and these phenomena has be well explained by the triangle theory.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.86-95
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• 2002

This paper suggests the new technology to control metal flow in order to reduce the number of preforming and the machining for the cold forged product with complex geometry. This technology is the combined forming that consists of bulk and sheet forming with double action dies. To analyze the process, finite element simulation has been performed. The proposed technology is applied to hub model that is part of air conditioner clutch. The purpose of this study is to investigate the material now of hub through the relative-velocity control of punch and mandrel using the flow control forming technique.

• Korea-Australia Rheology Journal
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• v.21 no.1
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• pp.71-79
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• 2009

The incomplete saturation and the void formation during the resin infiltration into fibrous porous media in the resin transfer molding process cause failure in the final product during its service. In order to better understand flow behavior during the filling process, a finite-element scheme for transient flow simulation across the micro-structured fibrous media is developed in the present work. A volume-of- fluid (VOF) method has been incorporated in the Eulerian frame to capture the evolution of flow front and the vertical periodic boundary condition has been combined to avoid unwanted wall effect. In the microscale simulation, we investigated the transient filling process in various fiber structures and discussed the mechanism leading to the flow fingering in the case of random fiber distribution. Effects of the filling pressure, the shear-thinning behavior of fluid and the volume fraction on the flow front have been investigated for both intra-tow and the inter-tow flows in dual-scale fiber tow models.

• The KSFM Journal of Fluid Machinery
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• v.11 no.4
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• pp.14-21
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• 2008

The prediction for gaseous leak flows through a narrow crack is important for a leak-before-break (LBB) analysis. Therefore, the methodology to obtain the flow characteristics of gaseous leak flow in a narrow crack for the wide range by using the product of friction factor and Reynolds number correlations (fRe) for a micro-channel is developed and presented. The correlation applied here was proposed by the previous study. The fourth-order Runge-Kutta method was employed to integrate the nonlinear ordinary differential equation for the pressure and the regular-Falsi method was also employed to find the inlet Mach number. A narrow crack whose opening displacement ranges from 10 to $100{\mu}m$ with a crack length in the range from 2 to 200mm was chosen for sample prediction. The present results are compared with both numerical simulation results and available experimental measurements. The results are in excellent agreement with them. The leak flow rate can be approximately predicted by using proposed methodology.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.179-183
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• 2006

Surface roughness is present in most of the microfluidic devices due to the microfabrication techniques. This paper presents lattice Boltzmann method (LBM) results for laminar flow in a microchannel with surface roughness. The surface roughness is modeled by an array of rectangular modules placed on top and bottom side of a parallel-plate channel. In this study, LBGK D2Q9 code in lattice Boltzmann Method is used to simulate flow field for low Reynolds number in a micro-channel. The effects of relative surface roughness, roughness distribution, roughness size and the results are presented in the form of the product of friction factor and Reynolds number. Finally, a significant increase in Poiseuille number is detected as the surface roughness is considered, while the effect of roughness on the microflow field depends on the surface roughness.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.03b
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• pp.138-144
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• 1996

In square die extrusion, flow guide and ide land play important roles for controlling the metal flow in die design. In the present work, the flow guide and the die land are considered for the die construction. Based on ALE description , rigid-viscoplastic finite element analysid is carried out to assess the effects of process and die design parameters. The thermal state affects greatly the product quality in hot extrusion. in the present work, the temperature distribution is also analyzed in theframwork of rigid-viscoplastic finite element computation. As a computational example, hot square die extrusion with flow guide and die land has been analyzed for the profile of a H section.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.84.1-84
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• 2001

Funded by the Singapore National Science and Technology Board (NSTB), CAMTech is collaborating with a Singaporean research institute and two industry partners with the objective to improve electronics assembly processes. The goal of this project is to visualise the behaviour of an electronics assembly industry by simulating, visualising the discrete events of the entire manufacturing processes and observing the flow of materials, size of buffers, and line balancing. The traditional scenario - from the customer placing order for a product to delivery - goes through various phases including manufacturing the product. Several major electronics manufacturing stages can be addressed: fabrication, assembly ...

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.10a
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• pp.99-104
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• 1996

A proform for engine valve was designed by finite element method. In the preform design of engine valve, various initial billets are simulated for better preform to get sound final product. Here a preform is design to get desirable metal flow in the forming so that the final product has more uniform strain distribution. after forming. The analysis of the micro-structure of the value formed through the designed process was also performed and result was compared with that of simulation.

• Journal of the Korean Society of Safety
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• v.3 no.1
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• pp.37-45
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• 1988

This research investigated the condition for plant design on reclamation of waste plastic by heat decomposition. The results were summarized as follows 1. The highest of oil product by heat decomposition is about 54.7％. 2. The optimum reaction temperature is about 300­40$0^{\circ}C$. 3. The optimum reaction time is 2­3 hours. 4. When the flow rate of 8­16 cm/sec in column reactor the yield is maximum. 5. Waste plastics yielded of carbon black product by heat decomposition at the optimum condition is about 23.5%. 6. Calorific values 0：1 were 9820 Kcal/kg.

• YAKHAK HOEJI
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• v.39 no.1
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• pp.68-77
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• 1995

Aluminum magnesium silicate was synthesized by reacting the mixed solutions of sodium aluminate and magnesium chloride with sodium silicate solution in this study. The optimal synthesis conditions based on the yield of the product has been attained according to Box-Wilson experimental design. It was found that the optimal synthetic conditions of aluminum magnesium silicate were as follows: Reaction temperature=$69~81^{\circ}C$; concentration of two reactants, sodium aluminate and magnesium chloride= 13.95~14.44 w/w%; molar concentration ratio of the two reactants, [NaAlO$_{2}$]/MgCl$_{2}$]=3.63~4.00; reaction time= 12~15 min; drying temp. of the product=$70~76^{\circ}C$. Aluminum magnesium silicate synthesized under the optimal synthesis condition was dispersed in 0.75, 1.0 and 1.5w/w% aqueous solution or suspension of six dispersing agents, and the Theological properties of the dispersed systems prepared have been investigated at $15^{\circ}C$ and $25^{\circ}C$ using Brookfield LVT Type Viscometer. The acid-consuming capacity of the most excellent product was 272~278 ml of 0.1N-HCl per gram of the antacid. The flow types of 5.0 w/w% aluminum magnesium silicate suspension were dependent upon the kind and concentration of dispersing agents added. The apparent viscosity of the suspension was generally increased with concentration of dispersing agents and was not significantly changed or decreased as the temperature was raised. A dispersing agent, hydroxypropyl cellulose suspension, exhibited an unique flow behavior of antithixotropy. The flow behavior of the suspension dispersed in a given dispersing agent not always coincided with that of the dispersing agent solution or suspension itself.