• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1547-1549
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• 1999

As a preliminary experiment for the development of anode-supported tubular cell with proper porosity, we have investigated the anode substrate and the electrolyte-coated anode tube. The anode substrate was manufactured as a function of carbon content in the range of 20 to 50 vol.%. As the caron content increased, the porosity of the anode substrate increased slightly and the carbon content with proper porosity was obtained at 30 vol.%. The anode tube was fabricated by extrusion process and the electrolyte layer was coated on the anode tube by slurry dipping process. The anode-supported tube was cofired successfully. Their sintered property and microstructure were examined and the porosity of the anode tube was 35%. From the gas permeation test, the anode tube was found to be porous enough for gas supply. On the other hand, the anode-supported tube with electrolyte layer indicated a very low gas permeation rate. This means that the coated electrolyte was dense. Based upon these experimental results. we will fabricate and test the anode-supported tubular cell.

• Journal of the Korean Society of Tobacco Science
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• v.10 no.1
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• pp.83-91
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• 1988

The effects of tipping paper permeability and plugwrap porosity on the ventilation and the pressure drop of cigarettes have been studied and the results obtained were as follows. 1. The single and the multiple regression equation to estimate tip ventilation were establised. In the equations, the observed values of the tip ventilation with the varieties the plugwrap porosity were content with them by the single regression equation. 2. As based on the statistical consideration of the above equation, the deviation of the observed tip ventilation versus the tipping paper permeability were higher than them to the plugwrap porosity. 3. The regression equations to calculate pressure drop ratio and the total ventilation rate in filter tip from the tea ventilation were obtained. According to the equation, the observed values of the pressure drop ratio were significantly similar to them calculated. 4. It was found that the equations could be applied to the calculation of the ventilation of cigarettes using the mechanical and micro laser perforation tipping paper as well as the electrically perforated tipping paper of this Study.

• Transactions of Materials Processing
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• v.22 no.6
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• pp.334-339
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• 2013

Direct Laser Melting is a prototyping process whereby a 3-D part is built layer wise by melting the metal powder with laser scanning. This process is strongly influenced by the shielding gas and the laser operating parameters such as laser power, scan rate, layering thickness, and rescanning. The shielding gas is especially important in affecting the microstructure and mechanical properties. In the current study, fabrication experiments were conducted in order to analyze the effect of shielding gas on the forming characteristics of direct laser melting. Cylindrical parts were produced from a Fe-Ni-Cr powder with a 200W fiber laser. Surface quality, porosity and hardness as a function of the layering thickness and shield gas were evaluated. By decreasing the layering thickness, the surface quality improved and porosity decreased. The selection of which shield gas, Ar or $N_2$, to obtain better surface quality, lower porosity, and higher hardness was examined. The formability and mechanical properties with a $N_2$ atmosphere are better than those parts formed under an Ar atmosphere.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.261-265
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• 2014

As the need for miniaturization in water purification filter increases, the development of filter media for single filtration with multiple function was strongly required. In this study, the molded activated carbon composed of single unit was manufactured by extrusion-sintering process, and then the flow rate, density and porosity were investigated using the molded activated carbon manufactured at various extrusion temperature. We confirmed that it was possible to manufacture the single unit-molded activated carbon when the extrusion temperature was $140{\sim}230^{\circ}C$ more than $133^{\circ}C$ being of polymer binder melting point, and the optimal extrusion temperature for the molded activated carbon with maximum flow rate was $170^{\circ}C$ since the molded activated carbon had low density and high through porosity. Also we confirmed that the flow rate through the molded activated carbon was strongly dependent upon through pore porosity compared to total porosity for the molded activated carbon.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.4 s.107
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• pp.77-82
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• 2004

Expression-deliquoring tests using three types of paper sludges (tissue, newsprint, and paperboard) as deliquoring agent were carried out in order to investigate the effects of sludge dosage and pressure on the expression-deliquoring of slurry. The addition of deli­quoring agent causes expression-deliquoring of slurry to be faster than would be the case without the deliquoring agent. In case of the tissue sludge, the highest compression rate was achieved when $5\%$ of deliquoring agent was added, while in cases of the news­print and the paperboard sludge, $7\%$. Compression rate was increased as pressure increases. Porosity was decreased as pressure increases. The lowest porosity was observed when $5\%$ of tissue sludge was added. When compared the weight of cake where deliquoring agent was not added and the weight of cake that was fastest expression-deliquoring, there was about $17.5\%$ of the weight reduction

• Proceedings of the Membrane Society of Korea Conference
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• 2002.07a
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• pp.59-101
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• 2002

PVDF is good material for a hollow fiber membrane with high porosity and excellent hydrophobicity. Asymmetric PVDF hollow fiber membranes were prepared by the Loeb-Sourirajan phase inversion method. Asymmetric PVDF hollow fiber membranes could be controlled in pore size and porosity using various additives(LiCl, ZnCl$_2$) and internal coagulants (water, EtOH/water, and DMAc/water mixture). $CO_2$removal efficiency of asymmetric PVDF hollow fiber membranes was 1.2 times high than that of commercialized PP hollow fiber membranes at MEA 5wt% solution. $CO_2$flux of asymmetric PVDF hollow fiber membranes was 2.5 times higher than that of commercialized PP hollow fiber membranes. $CO_2$removal efficiency and absorption rate of asymmetric PVDF hollow fiber membranes were 30 times higher than those of packed column at absorbent $H_2O$. $CO_2$flux of asymmetric PVDF hollow fiber membranes at MEA 5wt% solution was 48 times higher than that of pure water. In the case of MEA 5wt% solution used as an absorbent, the $CO_2$absorption rate and removal efficiency of PVDF hollow fiber membrane were 2.3 times higher than that of a packed column.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.537-542
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• 1996

In the present work the influence of various physical parameters on the two-phase flow behavior in a self-heated porous medium has been studied using a numerical model, that is, the effects of heat generation rate, of porosity, of particle size, and of system pressure on the dryout process. To analyze the effect of these parameters, the variation of both liquid volumetric fraction and liquid axial velocity is evaluated at the steady state or at the onset of a first boiled-out region. The analysis of computational results indicate that a qualitative tendency exists between the parameters such as heat generation rate, porosity, effective particle diameter and the temporal development of the liquid volumetric fraction field up to dryout. In addition to these parameters, a variation of fluid properties such as phase density, phase viscosity due to a change of system pressure can be used for gaining insight into the nature of two-phase flow behavior up to dryout.

• 한국전산유체공학회:학술대회논문집
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• 1997.10a
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• pp.120-125
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• 1997

In the present work the influence of various physical parameters on the two-phase flow behavior in a self-heated porous medium has been studied using a numerical model, that is, the effects of heat generation rate, of porosity, of particle size, and of system pressure on the dryout process. To analyze the effect of these parameters, the variation of both liquid volumetric fraction (i.e., liquid saturation) and liquid axial velocity is evaluated at the steady state or at the onset of a first boiled-out region. The analysis of computational results indicate that a qualitative tendency exists between the parameters such as heat generation rate, porosity, effective particle diameter and the temporal development of the liquid volumetric fraction field up to dryout. In addition to these parameters, a variation of fluid properties such as phase density, phase viscosity due to a change of system pressure can be used for gaining insight into the nature of two-phase flow behavior up to dryout.

• Journal of Environmental Science International
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• v.4 no.1
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• pp.29-40
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• 1995

Transport rate of windblown dusts such as soil, sand, snow is proportionate to $U*_^3 and U_*$, friction velocity, approximately to flow velocity of ink Therefore, through measurement and the flow velocity of wind, it turned out that, considering different velocity distributions caused by downstream distance and porosity percent, windbreaks with appropriate porosity rate to the Protection area should be chosen for the optimal fence effect. In the economic respects better are fences with gap of 20%~30%. Among the windbreaks to have the optimal fence effect.

• Journal of the Korean Society of Safety
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• v.11 no.2
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• pp.89-95
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• 1996

To predict the service life of an organic vapor respirator cartridge, the breakthrough curve of respirator was simulated using a fixed-bed adsorption model and compared with that of sampling tube. And the effects of bed porosity, length to diameter ratio and flow rate of the sampling tube were studied. The life time of respirator cartridge was increased with the decrease of particle size and bed porosity. And the breakthrough time of sampling tube was affected by the flow rate, however not by the length to diameter ratio. The 10% breakthrough time of the sampling tube was corresponded with that of cartridge.