• Proceedings of the Membrane Society of Korea Conference
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• 1999.10a
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• pp.39-39
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• 1999

Membrane separation technology has become a more attractive technology on waste water treatment and water recycle in recent years. On this application, membrane does not take main part of treatment, such as decomposition or handling of organic matter in the waste water, but it is very important supporting method in the total system. Activated sludge is most popular method as main part. In the system , membrane works as a separator to obtain clear water after biological treatment, by which the permeate could be released, recycled or applied to further additional treatment, instead of conventional sedimentation, coagulation and sand filtration. We would like to introduce our system cases for waste water treatment and water recycle, in which membrane separation technology works. In most of cases, membranes are applied to solid- liquid separation of activated sludge. Our experiences will be introduced as following items.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.2
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• pp.117-125
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• 2003

Experimental and theoretical works were performed for the separation of large polyelectrolyte, such as DNA, in a column packed with gel particles under the influence of an electric field. Since DNA quickly orient in the field direction through the pores, this paper presents how intraparticle convection affects the residence time distribution of DNAs in the column. The concept is further illustrated with examples from solid -liquid systems, for example, from chromatography Showing how the column efficiency is improved by the use of a n electric field. Dimensionless transient mass balance equations were derived, taking into consideration both diffusion and electrophoretic convection. The separation criteria are theoretically studied using two different Peclet numbers in the fluid and solid phases. These criteria were experimentally verified using two different DNAs via electrophoretic mobility measurements. which showed how the separation position of the DNAs varies in the column in relation to the Peg/Pef values of an individual DNA. The residence time distribution was solved by an operator theory and the characteristic method to yield the column response.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.186-187
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• 2013

The paper presents a long-pulse modulator for klystron using a high-voltage solid-state switch and a droop compensator. The modulator guarantees the safe of klystron by limiting the amount of energy transferred to klystron in case of arc. The high performance of the modulator is also achieved by the fast transition time, high flatness and average power. The proposed prototype has produced pulses with a flat-top voltage -90[kV], pulse width 1ms and pulse frequency 200[Hz]. The validity of the long-pulse modulator for klystron has been verified by the simulation and experimental works.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6458-6463
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• 2014

This study performed FEM analysis of a 38 person elevator brake. Recently, an emergency brake was newly developed to improve elevator safety. A 3D design was developed using Solid Works and FEM analysis using analysis code ANSYS. The total deformation, stress and strain were obtained.

• Environmental Engineering Research
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• v.19 no.4
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• pp.299-308
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• 2014

This study presents a review on Chemical looping combustion (CLC) development, design aspects and modeling. The CLC is in fact an unmixed combustion based on the transfer of oxygen to the fuel by a solid oxygen carrier material avoiding the direct contact between air and fuel. The CLC process is considered as a very promising combustion technology for power plants and chemical industries due to its inherent capability of $CO_2$ capturing, which avoids extra separation costs of the of $CO_2$ from the rest of flue gases. This review covers the issues related to oxygen carrier materials. The modeling works are reviewed and different aspects of modeling are considered, as well. The main drawbacks and future research and prospects are remarked.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.11a
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• pp.61-67
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• 2000

Many research works for improving a boundary lubrication performance have been executed by using solid lubricants, and been tried to apply an engine lubrication. However those general lubricants like MoS$_2$ or PTFE have not been applied on engines due to the extreme conditions such as very high temperature and pressure by combustion process in a cylinder. A copper nickel alloy fine particle has been introduced and studied. In this Paper the lubricant using the alloy Particles is applied on a marine diesel engine and assessed by the engine performance test The results showed the increase of cylinder pressure related strongly to the engine efficiency as well as the improving the engine lubrication performance.

• Journal of the Korean Chemical Society
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• v.55 no.6
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• pp.983-987
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• 2011

Surveys on the process of extracting acid from dried rinds of Garcinia oblongifolia Champ. ex Benth (G. oblongifolia) using microwave in terms of time, machine power and solid/liquid rate, have resulted in such findings as: the best time allocation for extracting is 25 minutes; machine power works best at level 2 (microwave power is 400 W); suitable rate of solid/liquid is 0.071 (approximately 150 mL solvent per 10 g of sample). The total amounts acid and (-)-hydroxycitric acid extracted from 100 g dried rinds of G. oblongifolia are 18.592 g and 10.137g respectively. This is the first finding on extraction of (-)-HCA from dried rinds of G. oblongifolia using microwave.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.4
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• pp.514-521
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• 2008

Many research works for improving a boundary lubrication performance have been executed by using solid lubricants, and been tried to apply an engine lubrication. However those general lubricants have not been applied on engines due to the extreme conditions such as very high temperature and pressure during combustion process in a cylinder. In this study a lubricant containing copper alloy nano-powder is applied on a diesel engine driven by an electric motor. Torques and shaft vibrations are measured, then an engine friction loss and rotating stability are assessed. The results show that the frequency of the vibration is about the same as that of a general lubricant, but the amplitudes in the both X and Y direction are reduced as well as the friction loss is reduced.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.71-77
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• 2001

We have developed the exclusive CAD/CAM system for the machining of impeller blades. This study is about the mod-eling method for the effective machining of impeller blades farmed by ruled surface. As the impeller is consisted of boss part and blade part, the boss is modeled by rotational surface of hub curve on z-axis and the blade is described by ruled- surfaces between hub curve and shroud curve. This modeling process can be carried out on the software developed in this study. And, the developed software can describe the impeller as a solid model through interface with Solid-Works soul- ware. The developed software containing the interface method proposed in this study was very effective fur impeller modeling.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2554-2557
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• 2008

Effect of a particle's spin is investigated numerically by considering the effect of lift occurring due to difference of rotations of a particle and of fluid such as the Saffman lift and Magnus force. These lift forces have been neglected in many previous works on particle-laden turbulence. The trajectory of particles can be changed by the lift forces, resulting in significant modification of the stochastic characteristics of heavy particles. Probability density functions and autocorrelations are examined of velocity, acceleration of solid particle and acceleration of fluid at the position of solid particle. Changes in velocity statistics are negligible but statistics related with acceleration are a little bit changed by particle's rotation. When a laden particle encounters with coherent structures during the motion, the particle's rotation might significantly affects the motion due to intermittently large fluid acceleration near coherent structures.