• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.33-37
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• 2004

Recently, Growing tendency for structure surface to use water repellent agent has increased steadily. But investigation of it's protection and durability property is not sufficient. Therefore, this paper shows the investigation about repellent property and micro structure's change in surface layer of mortar that is applied by water repellent agent. Water repellent property, absorption coefficient, air permeability, porosity and observation of micro construct was investigated according to water repellent agent type. The test results indicated that mortar applied water repellent agent appears tiny absorption coefficient, but air permeability is maintained. The reason is because silane solution is coating at capillary surface of a wall and minute pore structure is changeless.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.31-36
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• 2002

Recently, more interests in surface treatment of structure with water repellent agent are steadily increased, But, investigation of its properties such as protection, durability, morphology of micro structure is not sufficient. Therefore, This paper is aimed for the investigation of water repellent property and change of morphology of micro pores in mortar that is treated by water repellent agent(Inorganic polymer based material). Water repellent property, water absorption coefficient, air permeability, porosity and the observation of micro structure was investigated in different water repellent agent type. The test results indicated that water repellent treated mortar showed low absorption coefficient and air permeability(breathing effect). This is why inorganic polymer is coated at the wall of capillary and micro pores, also, the volume of micro pore is reduced without the change of morphology in micro structure.

• Fashion & Textile Research Journal
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• v.20 no.4
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• pp.457-463
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• 2018

This study examined the water absorption and drying properties of the thirteen types of the knitted fabrics for sports wear. These physical properties were analysed with relation to the constituent fiber cross-sectional shape and structure parameters of the knitted fabrics by regression analysis. Absorption and drying properties of the knitted fabric specimens were increased with increasing the porosity of the constituent yarns, which was attributed to the capillary channels in the yarns. The water absorption and drying properties were increased and decreased with increasing tightness factor and stitch density of the knitted fabric. The absorption property of the knitted fabric for perspiration absorption and fast dry sport-wear clothing was mostly influenced mostly by fiber cross-sectional shape and its characteristics, whereas, drying property was dependent on the structural parameters of the knitted fabric such as tightness factor and stitch density. Therefore, superior perspiration absorption and fast drying knitted fabric could be obtained in the fabric structure with optimum tightness factor and stitch density, and constituent yarn structure with non-circular fiber crosssection and high porosity. GATS method and MMT method are used to measure sweating fast drying properties and it is necessary to carry out studies using these measurement methods in order to compare with the results of this study.

• Journal of the Korean Ceramic Society
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• v.50 no.5
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• pp.341-347
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• 2013

Kaolin-based membranes with a pore size of 0.30-0.40 ${\mu}m$ were successfully prepared by a simple pressing route using low-cost starting materials, kaolin and sodium borate. The prepared green bodies were sintered at different temperatures ranging between 900 and $1200^{\circ}C$. The sintered membranes were characterized by X-ray diffraction, mercury porosimetry, scanning electron microscopy, and capillary flowmetry. It was observed that the porosity decreased with an increase in both the sintering temperature and the sodium borate content, whereas the flexural strength increased with an increase in both the sintering temperature and the sodium borate content. The air flow rate decreased with an increase in the sodium borate content. The typical porosity, flexural strength, and specific flow rate of the kaolin-based membrane sintered with 5 wt% sodium borate at $1100^{\circ}C$ were 37%, 19 MPa, and $1{\times}10^{-3}L/min/cm^2$, respectively, at a p of 30 psi.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.597-604
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• 2004

This work involves quantitatively investigating the correlation between reductions in strength and variations in pore structure under high temperature that can be utilized as estimation for predicting the inner temperature of member damaged by fire. The experimental results were remarkedly affected by micro-filling effect of silica fume and the different water-binder ratios. The increase of the exposure temperature caused the increase of porosity, which resulted from the reason that evaporable water in gel pore or capillary pores as well as chemically bound water was eliminated from hardened cement paste due to the dehydration of C-S-H and $Ca(OH)_2$. Thermal shrinkage of hardened cement paste gives rise to micro-crack, which cause the increase of porosity. Based on the experimental result that the increase of porosity is in charge of exposure temperature, how porosity is distributed can predict temperature-time history and assess the performance of concrete damaged by fire.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.953-960
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• 2012

An AMTEC (alkali metal thermal electric converter) is a device that is used for the direct conversion of heat to electricity. Sodium is used as the working fluid, and its circulation is driven by a capillary wick. The wicks used for circulation include an evaporator wick, artery wick, and condenser wick, and each wick has a pressure drop because of the circulation of liquid and vapor. For the circulation of sodium, the capillary pressure of the evaporator wick must be greater than the total pressure drop in the wicks. In this study, the pressure drop in the evaporator wick, artery wick, and condenser wick and the heat loss from the evaporator to the condenser through the artery wick were analyzed for the design of a 100 W AMTEC prototype. It was found that a particle diameter of 10 ${\mu}m$ is suitable for the evaporator wick to maintain a capillary pressure greater than total pressure drop in the circulation loop.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.522-527
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• 2015

Decision of available soil depth based on soil physical and hydraulic properties for the $3^{rd}$ Landscape Vegetation Project in the Incheon International Airport was attempted. The soil samples were collected from the 8 sites at different depths, 0-20 and 20-60cm, for the three project fields, A, B, and C area. Physical and chemical properties including particle size distribution, organic matter content and electrical conductivity were analyzed. Hydrological properties including bulk density and water holding capacity at different water potential, -6 kPa, -10 kPa, -33 kPa, and -1500 kPa were calculated by SPAW model of Saxton and Rawls (2006), and air entry value was calculated by Campbell model (1985). Based on physical and hydrological limitation, feasibility and design criteria of soil depth for vegetation and landfill were recommended. Since the soil salinity of the soil in area A area was $19.18dS\;m^{-1}$ in top soil and $22.27dS\;m^{-1}$ in deep soil, respectively, landscape vegetation without amendment would not be possible on this area. Available soil depth required for vegetation was 2.51 m that would secure root zone water holding capacity, capillary fringe, and porosity. Available soil depth required for landscape vegetation of the B area soil was 1.51 m including capillary fringe 0.14 m and available depth for 10% porosity 1.35 m. The soils in this area were feasible for landscape vegetation. The soil in area C was feasible for bottom fill purpose only due to low water holding capacity.

• Membrane Journal
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• v.28 no.3
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• pp.214-219
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• 2018

In the present study, superflux nickel capillary supports for gas and vapor separation membranes were prepared by a combined process of NIPS and sintering. Nickel capillary precursors were prepared by NIPS process from PSf-Ni-DMAC-PEG400 dope solution and was sintered at various temperatures in $H_2$ atmosphere to reliably produce Ni capillary support. The optimized Ni capillary support has an outer and inner diameters of 722 and $550{\mu}m$, and its thickness was $94{\mu}m$. It has 3-dimensional pore channel network and its porosity and mean pore diameter was 26% and $4{\mu}m$, respectively. Also, its mechanical strength was tested in tensile mode: its fracture load was 2.84 kgf and the fracture elongation was 13%. Finally, its single gas permeance was measured: He, $N_2$, $O_2$, and $CO_2$ permeance was 432,327, 281,119, 264,259, and 193,143 GPU, respectively. The superflux behavior could be explained from viscous flow through the macropores having a diameter of $4{\mu}m$ and narrow thickness. It could be concluded that the superflux behavior of the Ni capillary support was from the 3-D pore channel network and the small thickness.

• Journal of Powder Materials
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• v.22 no.2
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• pp.100-104
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• 2015

The porous metals are known as relatively excellent characteristic such as large surface area, light, lower heat capacity, high toughness and permeability. The Fe-Cr-Al alloys have high corrosion resistance, heat resistance and chemical stability for high temperature applications. And then many researches are developed the Fe-Cr-Al porous metals for exhaust gas filter, hydrogen reformer catalyst support and chemical filter. In this study, the Fe-Cr-Al porous metals are developed with Fe-22Cr-6Al(wt) powder using powder compaction method. The mean size of Fe-22Cr-6Al(wt) powders is about $42.69{\mu}m$. In order to control pore size and porosity, Fe-Cr-Al powders are sintered at $1200{\sim}1450^{\circ}C$ and different sintering maintenance as 1~4 hours. The powders are pressed on disk shapes of 3 mm thickness using uniaxial press machine and sintered in high vacuum condition. The pore properties are evaluated using capillary flow porometer. As sintering temperature increased, relative density is increased from 73% to 96% and porosity, pore size are decreased from 27 to 3.3%, from 3.1 to $1.8{\mu}m$ respectively. When the sintering time is increased, the relative density is also increased from 76.5% to 84.7% and porosity, pore size are decreased from 23.5% to 15.3%, from 2.7 to $2.08{\mu}m$ respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.1
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• pp.10-19
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• 1999

In 1991, the ministry of Gov't. Administration and Home Affairs set up a minimum of one sewage disposal plant in each province. By 1995, 264 models of the capillary infiltration method were set up in 331(78%) villages and the contact oxidation method was set up in 52 places. Since the Gov't. sent a letter to each responsible officer across the country stating their disapproval of the capillary infiltration method, the environmentally friendly sewage disposal system has not been diffused. The current model(mechanical sewage disposal) being used, in agricultural and fishing villages, costs too much for maintenance and operation(\50,000 per capita per year). In particular, because of the difference in sewage characteristics of agricultural and fishing villages from urban sewage, the efficiency of the disposal system is very low. Also, because of the growing need for more disposal plants, the Gov't. is looking for cheaper alternatives. This study has analyzed 2 kinds of sewage disposal. The first is used widely in agricultural and fishing villages in Germany. The second is used widely in similar areas of Korea. It has intended to analyze the characteristics, merits and defects of the sewage disposal water plants and pebbles model which is used widely in Germany and developed compatibly for Korea.