• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.103-111
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• 2009

Moisture is one of the important design factors that affects to the changes of physical properties and air permeability in the composting matrix. This study examines the effects of moisture during the wetting and drying procedure on physical properties like bulk density, particle size, free air space and air permeability in the sawdust used as the bulking agent in composting process. During both procedures of wetting and drying of the water, with increasing moisture content, bulk density and particle size increased, but FAS decreased. In the range of near 40 to 60% moisture content on a wet basis, particle size and FAS in wetting procedure were larger and higher than those in drying procedure. During wetting procedure, pressure drop continuously decreased ranging from near 20 to 60% moisture content, despite of decreasing FAS as a consequence of increasing moisture, and then over the range of 60% moisture content, pressure drop rapidly increased to the saturated moisture condition while the pore space was filled with the water. On the other hand, during drying procedure, pressure drop decreased from the saturated condition to 40% moisture content. In the recommended range of 50 to 60% moisture content for composting operation, pressure drop in wetting procedure were lower than in drying procedure. For the enhancement of the air permeability in the composting matrix, the wetting procedure was proper than the drying procedure, and the optimum moisture content for the efficient composting operation was appeared to be near 60%.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.1
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• pp.1-10
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• 1987

We selected four kinds of cotton velvet and chafed before and after cleaning, then in accordance with abrasion times we measured of pile exclusion rate and examined the relationship of the pile exclusion rate, its thickness and the air permeability. An experimental study was carried out the pile weave construction, the density, the yarn to yarn, the shrinkage, and the pile substantiality. The results were as follows: 1. In accordance with increments of shrinkage phenomenon of pile fabric for cleaning process, pile exclusion rate was decreased. 2. The ground weave of pile fabric and the yarn to yarn of warp and weft direction were affected by the pile exclusion. 3. It is linear of pile substantiality of pile fabric and pile fastness. 4. In estimation of pile exclusion rate, it is proper to make use of air permeability and measuring value of thickness.

• Textile Coloration and Finishing
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• v.14 no.6
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• pp.313-318
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• 2002

Chitosan is known to be an excellent biocompatible natural polymer. Recently, with a growing interest of health and environment, chitosan which is good in no harmful effect on human body and environment, has been watched as the finish treatment of hygiene and pleasantness. The purpose of this study is to develop multi functional fabrics by chitosan added on acrylic acid grafted cotton fabrics. Therefore physical properties such as moisture regain, air permeability, whiteness, static voltage and tensile strength of chitosan added on acrylic acid grafted cotton fabrics were investigated. The results are as follows ; According to increased chitosan's concentration, grafting yield was decreased. Therefore thickness of film by treated chitosan added on acrylic acid grafted cotton fabric became thin. FT R spectra of chitosan add on acrylic acid grafted cotton fabric clearly showed peaks of COOH and $NH_2$, Moisture regain, static voltage of chitosan add on acrylic acid grafted cotton fabrics were increased than control. Air permeability, whiteness and tensile strength were decreased than control.

• Journal of the Korea Concrete Institute
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• v.12 no.1
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• pp.33-44
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• 2000

Since the mechanism of chloride diffusion and its ratio in concrete depend on structural conditions and concrete as a micro-structure, if these are analyzed quantitatively, the long-term ageing of structures can be predicted. Although, a quantitative analysis of concrete micro-structure, in which the results are affected by various parameters, is very difficult, this can be done indirectly by the durability test of concrete. In this study, the compressive strength, void ratio and air permeability of concrete. In this study, the compressive strength, void ratio and air permeability of concrete are chosen as the parameters in concrete durability test, and these effects on test results are analysed according to changes of mixing properties. The relationships between parameters and chloride diffusion velocity is used for prediction models of chloride diffusion. The developed prediction models for the chloride diffusion according to mixing and physical properties, can be used to estimate the service life and corrosion initiation of reinforcing bars in marine structures.

• Journal of the Korean Home Economics Association
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• v.17 no.4
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• pp.23-28
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• 1979

In order to measure the change of constructional and some properties of knitted under wears by laundry, constructional properties, such as fabric count , yarn count, loop length and cover, factor, and some properties , such as shrinkage, tearing, strength, air permeability, electrostatic charge of under wears sold in the market were tested. The results of the experiment can be summarized as follows.1. Interlock and rib were increased in wale direction after laundry and decreased in course direction , plain was decreased, in both direction after laundry. 2. Loop form of plain was changed more than those interlock and rib after laundry. 3. Tearing strength was decreased 51% in wale direction, and 70% in course direction after 20 times laundry. Air permeability was generally increased. 4. Electro static charge was increased 9 times after laundry.

• Fashion & Textile Research Journal
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• v.12 no.2
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• pp.219-223
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• 2010

In this study, the comfort properties of cotton and Hanjee fabrics dyed with Inonotus obliquus and treated with illite were evaluated and compared. Results were as follows; 1) W/T values and WC/W values of cotton and Hanjee fabrics were decreased when they were dyed with Inonotus obliquus and treated with illite. 2) Although air permeability of cotton fabrics was higher than that of Hanjee fabrics, air permeability of cotton and Hanjee fabrics dyed with Inonotus obliquus and treated with illite was decreased. 3) Thermal conductivity of cotton and Hanjee fabrics dyed with Inonotus obliquus was increased whereas thermal retain property was decreased. 4) Water absorption of Hanjee fabrics was higher than that of cotton fabrics. Water absorption of cotton and Hanjee fabrics dyed with Inonotus obliquus and treated with illite was increased. 5) Deodorization rate of Hanjee fabrics was greater than that of cotton fabrics.

• Journal of the Korean Home Economics Association
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• v.19 no.2
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• pp.143-149
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• 1981

Consumer consider the purpose for which they plan to use clothes when they purchase it, and the socks in textile products is evaluated in the same way. serviceability is judged by the extent to which the socks will be useful for its intended purpose. It should retain its original shape and size, good air permeability, good absorbency, good abrasion resistance, high fastness etc. Owing to importance of serviceability in socks, in this paper, these end-use requirement characteristics were tested. The results obtained were as follows: 1. Blend ratios were different between the indicated fiber contents on labels and the testing ones. 2. Air permeability was higher in the samples which contain less stitch density, and hydroscopicity was higher in those which contain natural fibers such as cotton and wool. 3. Shrinkage depended on the blend ratios of cotton and wool, and elastic recovery was better in the course direction than in the wale direction. 4. Pilling was conspicuous in the synthetic fibers such as polyester and nylon, and fastness of laundering and perspiration was higher in the fading grade than in the staining grade.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.813-816
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• 2006

Recently, improvements in the standard of living in industrial area require the establishment of a convenient residential environment in order to enhance the quality of living. To achieve such an environment, it is necessary to effectively reduce or prevent various environmental problems occurring in and around residential areas. Although conventional concrete has been regarded as a destroyer of nature, water and air can pass freely through concrete when it is made porous concrete by forming continuous void. In view of the harmony between nature and concrete, various research paths are being taken focusing on coarse aggregates to make porous concrete having continuous voids so as to improve water and air permeability, acoustic absorption, water purification, and applicability to vegetation. In this study, the Physical and Mechanical Properties of porous concrete according to compaction method analyzed by void ratio, coefficient of permeability and compressive strength.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.1
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• pp.9-14
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• 2008

Beating and using chemical agents are common methods to improve physical properties. But the beating is high energy consumption process and chemical agent addition may cause deteriorate waste water quality. Therefore, it is necessary to use more environment-friendly methods. In this study, micro pulp was used in the handsheet making to get improving effects of physical properties without beating treatment and chemicals. Stiffness, thickness and air permeability were increased and strength properties of paper were also improved to some extents by only the micro pulp addition.

• Korean Journal of Metals and Materials
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• v.50 no.5
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• pp.389-393
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• 2012

Improvement in microwave absorbance has been investigated by insertion of a periodic air cavity in rubber composites filled with magnetic powders. A mixture of $Co_2Z$ hexagonal ferrite and Fe powders were used as the absorbent fillers in silicone rubber matrix. The complex permeability and complex permittivity of the magnetic composites were measured by reflection/transmission technique. In the grid-type magnetic absorbers, the equivalent permeability (${\mu}_{eq}$) and permittivity (${\varepsilon}_{eq}$) are calculated as a function of air volume rate (K) on the basis of effective medium theory. Reduction in the material parameters (especially, dielectric permittivity and magnetic loss) has been estimated with the increase of K. Plotting the ${\mu}_{eq}$ and ${\varepsilon}_{eq}$ on the solution map of wave-impedance matching, wide bandwidth microwave absorbance has been predicted in the magnetic composites with an optimum value of K.