• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.113-120
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• 2010

Air-cathode microbial fuel cell consisted of 4 unit cells were operated under batch condition and electricity generation and microbial community structure variation were investigated, depending on separator types and cathode characteristics: A) PEM(Proton Exchange Membrane)-30% Wet proofing Carbon Cloth(WC), B) AEM(Anion Exchange Membrane-WC, C) CEM(Cation Exchange Membrane)-WC, D) PEM-No Wet proofing Carbon Cloth(NC). Maximum power densities of PEM-WC, AEM-WC and CEM-WC were 510.9, 522.1 and 504.8 $mW/m^2$, respectively. But PEM-NC showed relatively lower maximum power density of 218.3 $mW/m^2$. And PEM-WC, AEM-WC and CEM-WC showed similar internal resistances(20.0-28.2 ${\Omega}$). PCRDGGE, PCA and diversity indices showed that uncultured bacteria which reported in previous MFC studies were detected in suspended growth bacteria and attached growth bacteria would be affected not by separator type but by cathode characteristic. Thus, cathode characteristic can be one of the critical factors for power generation in air-cathode MFC using PEM, AEM, and CEM as separator.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.254-262
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• 2003

Effect of the air distributor pore size for the removal of aquacultural waste, such as protein, total suspended solids (TSS), chemical oxygen demand (COD), turbidity and total ammonia nitrogen (TAN) from sea water was investigated by using foam separator. With the increase of pore size of air distributor, removal rates and efficiency of protein decreased. Removal rate by commercial air stone was in the range between the removal rates by G2 and G4 sintered glass discs. Within the range of pore size distributor from Gl to G4, the removal efficiency of protein were ranged from 21 to $42\%.$ The changes of removal rates and efficiencies of TSS, COD and turbidity were similar to proteins. TAN was removed by stripping. The pore size of air distributor for a higher overall oxygen mass transfer coefficient and saturation efficiency provided the condition for higher protein removal rate. Also the foam separator could be used as an aerator.

• Journal of computational fluids engineering
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• v.20 no.4
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• pp.81-92
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• 2015

Construction waste mainly consists of concrete aggregates of various size. Improper handling of concrete waste would be a major environmental problem whereas its recycling would be both economically useful and environmentally friendly. Bigger concrete aggregates are crushed and converted to medium and fine particles to make them recyclable. An apparatus to separate the concrete aggregates by their size is thus needed for their effective recycling. In this work, segregation of concrete particles in air flows from a newly designed rotary separator having three stages of blades is simulated using a commercial software, ANSYS-CFX. Both 2-D and 3-D models with 360, 240 and 180 blades in each stage are considered. Fundamental mechanism of separation of particles(pase) and the effect of design parameters such as particle size, rotor speed, air flow rate etc. on the performance of the separator are investigated. Critical size of particles that can be separated by the developed separator is also presented in this work. Simulation results are overall in good agreement with data predicted from the theoretical model previously reported in the companion paper.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3215-3220
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• 2007

Gas-liquid separator has been designed for the sake of reducing expenses associated with production operations. To date, a number of gas-liquid separators have been installed and put to use for various applications. Despite the advantages of simple and compact configuration of separator with no moving part, its efficient operation is limited in terms of total pressure losses, separation performance and flow-induced noise and vibration, which are closely associated with the very complicated flow phenomena involved. In the present study, a gas-liquid centrifugal separator with a swirl vane is investigated for the purpose of water separation from compressed moisture air. The 3D Navier-Stokes equations are numerically solved using a fully implicit finite volume scheme. Based upon the obtained solutions, tangential velocities, centrifugal forces, vortices and total pressure losses are analyzed to find out the best design parameters. From the present study, several attempts are made to improve the performance of conventional separators of centrifugal type.

• Journal of Electrochemical Science and Technology
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• v.2 no.1
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• pp.51-56
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• 2011

We develop a new nonwoven composite separator for a safer lithium-ion battery, which is based on coating of silica ($SiO_2$) colloidal particles/styrene-butadiene rubber (SBR) binder to a poly(ethylene terephthalate) (PET) nonwoven support. The $SiO_2$ particles are interconnected by the SBR binder and closely packed in the nonwoven composite separator, which thus allows for the development of unusual porous structure, i.e. highly-connected interstitial voids formed between the $SiO_2$ particles. The PET nonwoven serves as a mechanical support that contributes to suppressing thermal shrinkage of the nonwoven composite separator. The $SiO_2$/SBR content in the nonwoven composite separators plays an important role in determining their separator properties. Porous structure, air permeability, and electrolyte wettability of the nonwoven composite separators, in comparison to a commercialized polyethylene (PE) separator, are elucidated as a function of the $SiO_2$/SBR content. Based on this understanding of the nonwoven composite separators, the effect of $SiO_2$/SBR content on the electrochemical performances such as self-discharge, discharge capacity, and discharge C-rate capability of cells assembled with the nonwoven composite separators is investigated.

• Journal of Magnetics
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• v.21 no.4
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• pp.635-643
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• 2016

Improvements were made in the study for the design of the conventional Eddy Current Separator (ECS) used for separating small sized non-ferrous particles in the waste. These improvements include decreasing the air gap between the material and magnetic drum, making the drum position adjustable and placing the splitter closer to the drum. Thus, small particles were separated with high efficiency. The magnetic drum was removed from inside the ECS conveyor belt system as design change and was placed as a separate unit. Hence, the force generated on the test material increased by about 5.5 times while the air gap between the non-ferrous materials and drum decreased from 3 mm to 1 mm. The non-metal material in the waste is separated before the drum in the novel design. Whereas non-ferrous metal particles are separated by falling into the splitter as a result of the force generated as soon as the particles fall on the drum. Every material that passes through the drum can be recycled as a result of moving the splitter closer to the contact point of the drum. In addition, the drum can also be used for the efficient separation of large particles since its position can be adjusted according to the size of the waste material. The performance of the novel design ECS was verified via analytical approaches, finite element analysis (FEA) and experimental studies.

• Membrane Journal
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• v.24 no.1
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• pp.10-19
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• 2014

Porous flat sheet membranes for separators in Zn air batteries were prepared with polyethersulfone (PES) solutions by immersion precipitation phase inversion method. PES/polyvinylpyrrolidone(PVP)/N-methylpyrrolidone(NMP) mixtures were used for casting solutions and water was used for coagulant. With the separators, Zn air batteries were fabricated. The separators were characterized by means of stress-strain test, impedance test and SEM. The Zn air batteries were tested by current interrupt method (CIM) and galvanostatic discharge method. The tensile strength increased with increasing PES content in the casting solution while the ionic conductivity decreased. On the other hand, the ionic conductivity increased while the tensile strength decreased with increasing PVP content. The effect of ionic conductivity trend of the separator in the Zn air battery was confirmed through current interrupt method and galvanostatic discharge method experiments. The battery with the separator from casting solution with higher PES content showed higher IR drop and lower discharge capacity. And the battery with the separator from casting solution with higher PVP content showed lower IR drop and higher discharge capacity.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.586-591
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• 2013

This experiment was performed to enhance $CH_4$ purity of landfill gas by applying gas separator membrane for purified nitrogen gas production. 1:6 area ratios of $1^{st}$ to $2^{nd}$ membrane module was suitable for $CH_4$ recovery. After separation membrane system was installed, 249 tries were performed. Average permeability for $CH_4$ was 28.4% and for $CO_2$ was 94.3%. This can explain nitrogen gas separator membrane can be applied to collect $CH_4$ from LFG. However, nitrogen permeability only reached up to 16.5%. Therefore, the final purified landfill gas concentration was rounded up to 69.7% for $CH_4$, 4.3% for $CO_2$ and 26.0% for $N_2$. For the high degree of $CH_4$ purity, $N_2$ should be kept at least under 2.0% by controlling air inflow to landfill.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.165-169
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• 1999

Experiments were conducted to evaluate a experimental model developed for the protein removal by foam separation. The foam separator was operated in well-mixed tank which would be considered as a completely mixed condition. The feasibility of foam separation to remove protein from sea water was investigated. Protein removal characteristics of the foam separator were obtained by batch experiments. To find the effect of the operating parameter to protein removal rate, the foam separation was carried with variation of initial protein concentration and superficial air velocity. The result indicated that the protein removal efficiency was increased with increasing protein concentration and superficial air velocity. The relationship between operation parameters and protein removal rate were evaluated by non-linear regression as the form of exponential function, Using both relationships, the simplified model was determined. The simplified foam separator operation model was verified by the batch operation. The simulation results showed a good relationship with the experimental data.

• Polymer(Korea)
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• v.34 no.6
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• pp.517-521
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• 2010

Microprous polyethylene (PE) membranes are widely used as lithium-ion battery separators. A separator having higher meltdown temperature than PE separator is still required for useful safety feature at a high temperature. To enhance meltdown temperature of PE separator, it was coated with polymers synthesized from bis-GMA derivatives by radical polymerization. Polymer was not formed when bis-GMA monomer having a high viscosity was used, while polymers were formed when bis-GMA derivatives having a low viscosity were used. When the separator was coated with polymer synthesized from reaction mixture containing proper amount of bis-GMA derivative, its meltdown temperature were increased up to $160^{\circ}C$ without reduction in the air permeability.