• Proceedings of the Membrane Society of Korea Conference
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• 2001.10a
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• pp.39-50
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• 2001

The performance of membranes is governed their pore struture. Pore structures of porous materials can be determined by a number of techniques. However, The novel technique, capillary folw porometry has a number of advantages. In this technique, the sample is brought in contact with a liquid that fills the pores in the membrane spontaneously. Gas under pressure is used to force the liquid from the pores and increase gas flow. Gas flow rate measured as a function of gas pressure in wet and dry samples yield data on the largest pore size, the mean flow pore size, flow distribution and permeability. Pore characteristics of a number of membranes were measured using this technique. This technique did not require the use of any toxic material and the pressure employed was low. Capillary flow porometry is a suitable technique for measurement of the pore structure of many membranes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.3
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• pp.445-456
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• 1997

Continuous casting process is numerically analyzed using the continuum model in a non-orthogonal coordinate system. Flow damping in the mush is modeled by combining the viscosity dependence on liquid fraction in dilute mush and the permeability dependence on liquid fraction in concentrated mush. The effect of turbulence is indirectly considered by effective diffusivity determined elsewhere by experiment. The main objective is to investigate the effects of casting parameters such as casting speed and tundish superheat on the distribution of surface temperature, shell thickness, metallurgical length and centerline segregation. Some of the computed results are compared with available experiments, and reasonable agreements are obtained.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.202-206
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• 2001

The characteristics of heat transfer on the fire clay with microwave heating are numerically investigated using finite element method. The modelled regular hexahedron chamber($50cm{\times}50cm{\times}50cm$) filled with air consists of vertical heat source and sink walls, a fire clay model, and adiabatic plates at the top and bottom walls. With different geometrical aspect ratios of the fire clay model, the heat energy distribution is throughly investigated. The optimal shape of the fire clay for given chamber geometry and microwave power is analyzed.

• Textile Coloration and Finishing
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• v.6 no.4
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• pp.40-45
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• 1994

To improve the blood compatibility of cellulose membrane, 2-(methacryloyloxy)ethyl-2-(trimethylammonium)ethyl phosphate(MTP), which is a methacrylate with phospholipid polar group, and glycidyl methacrylate(GMA) were grafted simultaneously on the surface of membrane and the biocompatibility of grafted membrane was investigated. There was no difference of permeability between the MTP and GMA-grafted and the original cellulose membrane. The permeation pathway for a solute whose molecular weight was above 10$^{4}$ is maintained after grafting on the surface of membrane. The cellulose membrane grafted with MTP and GMA effectively suppressed thrombogenicity for the rabbit blood. This effect became more clear with increasing the surface distribution of phospholipid polar groups.

• Journal of Fashion Business
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• v.12 no.4
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• pp.131-142
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• 2008

One of the major fashion trends is the naturalism and ecology-conscious trend. The natural looks required in the trend require somewhat random distribution of yarn linear density, which results in irregular appearance along the yarn. This is a technically challenging work of producing yarns that look natural far from being artificial yet maintaining the intricately aesthetic randomness without causing process disturbances. This study focused on the characteristics of fabrics made of natural cellulosic fibers including hemp, ramie, flax, and polyester fabrics. Image analysis of the fabric samples included area measurement of yarn specimen, FFT and inverse FFT. Measurements of bending resistance, thickness, air permeability, and weight were also implemented to interpret the structural differences.

• Proceedings of the Korean Quaternary Association Conference
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• 2005.06a
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• pp.7-11
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• 2005

The soil erosion processes have estimated using spatial distribution of 137Cs radionuclide in Granite and Sedimentary Hillslopes in South Korea. The local variability of 137Cs inventory indicates that was related positively to organic matter content, clay content and water content and negatively to hydraulic permeability and slope gradient for bulk samples in different landforms within Granite and Sedimentary rock basins. The vertical variability of 137Cs inventory shows that most of 137Cs concentration and organic matter were accumulated between 0 and 2cms and gradually decrease with soil depth in incremental samples in both basins. The vertical variability of 137Cs inventories shows that 137Csinventories increase as we go to toward downslope in both basins. Finally, the soil loss values indicate that hillslope erosion processes are more intensive in Granite rock basin than those in Sedimentary rock basin.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.157-164
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• 2004

Air voids in hardened concrete have an important influence on concrete durability such as resistance of freezing and thawing, permeability and surface scaling resistance. Linear traverse method and point count method in ASTM standard method have been widely used to estimate the air void system in hardened concrete. However, these methods are not used at present time, because they are is exhausted much time and effort. In previous study, air voids system of concrete was estimated by spacing factor. The purpose of this study organizes image analysis method by analyzing air contents, air voids distributions by diameters, air voids system as well as spacing factors after hardened concrete. The experimental variables institute of depth of specimen(top, middle, bottom), air contents(AE contents 0, 0.01, 0.03%).

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.617-620
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• 2006

This study is related to comprehending performance for watertightness and crack control of concrete added with crack reducing agent concerning to high strength concrete mixs. It was confirmed that watertightness of concrete added with agent could be improved by evaluation absorption ratio, permeability ratio and pore size distribution of hardened concrete. As well resistance to crack resulted from shrinkage was transferred to better state by the addition of agent.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.925-930
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• 2006

Chitosan-based nanocomposite films were prepared using a solution intercalation method incorporating varying amounts of organically modified montmorillonite (Cloisite 30B) from 0 to 30 wt%. The nanocomposite films prepared were optically clear despite a slight decrease in the transmittance due to the spatial distribution of nanoclay. X-ray diffraction patterns indicated that a certain degree of intercalation or exfoliation formed when the amount of clay in the film was low and that microscale tactoids formed when the clay content in the sample was high (more than 10 wt%). The tensile strength (TS) of the chitosan film increased when the clay was incorporated up to 10 wt% and then decreased with further increases in the clay content of the film. The elongation at break (E) increased slightly upon the addition of low levels of clay up to 5 wt% and then decreased with further increases in the amount of the clay in the film. The water vapor permeability (WVP) decreased exponentially with increasing clay content. The water solubility (WS) and swelling ratio (SR) of the nanocomposite films decreased slightly, indicating that the water resistance of the chitosan film increased due to the incorporation of the nanoclay.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.317-327
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• 2001

For soils with high void ratios, the inverse method of utilizing results obtained from centrifuge model test was used to find the constitutive relation of effective stress - void ratio - permeability whereas conventional oedometer test and constant rate of strain consolidation test were also used to fine its relation at ranges of relatively low void ratio. Results of column test about settlement of interface and pore pressure and distribution with time were compared with numerically estimated values to confirm such a constitutive relation as obtained from the inverse method. Consolidational settlement in dredged and reclaimed ground, where the consolidation was in progress, was predicted by using the numerical technique implemented with the finite strain consolidation theory.