• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.229-230
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• 2003

In these days, it is actively investigated to use loess in textile industry. The loess have been reported for emissivity of far-infrared and negative ion, and antibacterial efficacy. The loess consist of quartz, feldspar, clay mineral, iron oxide mineral, gibbsite [Al(OH)$_3$], etc. The main component of loess is clay minerals which have great adsorption about ion exchange and far-infrared emission properties. Recently, various inner-wears, sheets, and interior goods are manufactured using the loess due to its improved blood circulation, metabolism, antibacterial and deodorizing properties. (omitted)

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.218-219
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• 2005

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.2
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• pp.134-139
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• 2012

Objectives: This study was conducted to study the analytical variability of A & B counting rules in counting using a phase contrast microscope airborne fibers collected on filters in man-made mineral or vitreous fibers (MMMFs) industries. Methods: Fibers in filters were counted using A & B rules of NIOSH Method 7400. Intra-counter and inter-counter variations by fiber type and density were obtained. The types of MMMFs analyzed were glass wool fiber, rock wool fiber, slag wool fiber, and refractory ceramic fibers. The densities of fibers classified were <20 $fibers/mm^2,$ 20 - <50 $fibers/mm^2$, 50 - <100 $fibers/mm^2,$ and ${\geq}100$ $fibers/mm^2,$ respectively. Results: Intra-counter relative standard deviations by rule A were 0.084, 0.102, 0.071 for glass wool fibers, rock wool fibers and refractory ceramic fibers, and those by rule B were 0.139, 0.120 and 0.142, respectively. Inter-counter relative standard deviations by rule A were 0.281, 0.296, 0.180 for glass wool fibers, rock wool fibers and refractory ceramic fibers, and those by rule B were 0.396, 0.337 and 0.238, respectively. Conclusions: Intra-counter variation was not different significantly among fiber types (p>0.05), but B rule variation for ceramic fibers approximately 2 times greater than corresponding A rule estimates, and intra-counter and inter-counter variations were higher in the low fiber density.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.894-899
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• 2012

In recent years, recycling process has come to be necessary for separating metals, glass fibers and polymer from WPCBs (waste printed circuit boards) due to an increasing amount of electronic device waste. In this study, dimethylformamide (DMF) and attrition mill reactor were used to separate the component such as metals, glass fiber and epoxy resin from WPCBs. Separation of glass fiber from WPCBs was carried out under stirring rates 300~600 revolution per minute (rpm) for 1~2 h as the various agitator. The recycled glass fibers (RGF) were analyzed by thermogravimetric analyzer (TGA) for degree of separation of epoxy resin in the WPCBs. The degree of separation of epoxy resin of WPCBs increased in attrition mill agitator as a mechanochemical process for recycling WPCBs. The RGF separated in the WPCBs was applied as a reinforcement in the RGF/unsaturated polyester composites to reuse as a reinforcement.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.21-28
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• 2000

Various man-made mineral fibers(MMMF) including refractory ceramic fiber(RCF) have been used widely in industries as insulation materials. The effect of fibrous dust on human health depends on fiber size, concentration (exposure level), and durability in biological system. Therefore, these parameters should be determined to evaluate accurately the potential risk of fibers on human health. The purpose of this study was to characterize the size of airborne fiber and the workers＇ exposure to airborne fibers in refractory ceramic fiber manufacturing and processing factories. Airborne fibers were collected on 25-mm mixed cellulose ester membrane filters at personal breathing zones, and analyzed by A and B counting rules of the National Institute for Occupational Safety and Health(NIOSH) Method # 7400. The average ratios of the fiber density by B rule to the fiber density by A rule was 0.84. This result indicates that the proportion of respirable fibers (<3 ${\mu}{\textrm}{m}$ diameter) in air samples was high. The average diameter and length of airborne fibers were 1.05${\mu}{\textrm}{m}$ and 35${\mu}{\textrm}{m}$, respectively. The average fiber concentrations (GM) of all personal samples was 0.26f/cc, and the average concentration was highest at blanket cutting and packing processes. The fifty seven percent of personal air samples was exceeded the proposed American Conference of Governmental Industrial Hygienists(ACGIH) Threshold Limit Value(TLV), i.e. 0.2 f/cc. It was concluded that the RCF industrial workers had the higher potential health risk due to small fiber diameter, long fiber length, and high exposure level to the airborne fibers.

• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.339-346
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• 2011

The effects of mineral admixtures on the bonding properties of cement mortar to polyolefin based synthetic fiber were evaluated. The mineral admixtures consisted of 0%, 5%, 10%, and 15% fly ash, blast furnace slag, and metakaolin in cement. Bond interactions between the cement mortar and the polyolefin based synthetic fiber were determined by Dog-bone bond tests. Bond tests of the polyolefin based synthetic fiber showed an increase in pullout load with the strength of the cement mortar. Also, the interface toughness of polyolefin based synthetic fiber in cement mortar increased as the fly ash, blast furnace slag, and metakaolin contents increased. The microstructure of polyolefin based synthetic fiber surface was examined after the pullout test to analyze the frictional resistant force according to the replacement ratio of fly ash, blast furnace slag, and metakaolin during the pullout process of polyolefin based synthetic fiber in cement mortar. The scratched of polyolefin based synthetic fibers increased with the replacement ratio of fly ash, blast furnace slag, and metakaolin. Also, the interface toughness was enhanced by adhesion forces induced by the fly ash, blast furnace slag, and metakaolin.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.1
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• pp.28-34
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• 1997

This study was conducted to determine the protein content, cell wall fractions, and mineral concentrations of some minor plant species collected for one year in pastures grazed by goats in the Philippines. An assessment of nutrient variability and a comparison of forage protein and mineral concentrations to the critical value of protein and minerals based on animal needs were also studied. The plant species were the following: grasses(Axonopus compressus, Eleusine indica, Rottboellia exaltata); legumes (Aeschynomene indica, Calopogonium muconoides, Desmodium tortousum); and herbs (Corchorus olitorius, Ipomea aquatica, Sida acuta, Synedrella nodiflora). The two seasons (dry and wet) were subdivided into Dry-1 (December to February, 132 mm total rainfall), Dry-2 (March to May, 25 mm total rainfall), Wet-1 (June to August, 1,138 mm total rainfall), and Wet-2 (September to November, 1,118 mm total rainfall). Results showed that significant differences were obtained on various nutrient fractions including those mineral concentrations across species. Across season, acid detergent lignin (ADL) had higher (p < 0.05) value at Dry-1. Legumes and herbs were higher in crude protein (CP) especially Sida acuta. Grasses showed the highest neutral detergent fiber (NDF) and acid detergent fiber (ADF) with the addition of Sida nodiflora (herb) for it contained high NDF. Aeschynomene indica contained the highest amount of ADL and the herbs (Ipomea aquatica and Sida acuta) had exceptionally high concentration of minerals. Coefficient variation of the various nutrient values ranged from 27.3 to 136.7%. Some forage minerals appeared to be deficient (sodium, phosphorus and copper) or excess (molybdenum) for the whole or part of the year. This study shows that some minor plant species could extend the range of concentration of some nutrients (i.e., CP and minerals) beyond that normally found in conventional pasture species.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1162-1167
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• 2004

From the early 1980's, the New Austrian Tunnelling Method (NATM) has been developed as a one of the standard tunneling method in Korea. Owing to the results of many researches, the practical problems of shotcrete has been improved for a last decade. However, the excess amount of rebound still remains one of the critical problems in shotcrete technology. In order to improve for this rebound problem, recently developed cement mineral accelerator has been successfully applied to several NATM tunnels in Korea. An experimental investigation was carried out in order to verify the rebound characteristics of wet-mix Steel Fiber Reinforced Shotcrete (SFRS) with powder types cement mineral accelerator. Mortar setting test, SEM analysis, bonding test under spring water condition and rebound test were conducted. From the result, wet-mix SFRS with cement mineral acelerator exhibited excellent bonding characteristics even spring water condition and less rebound ratio compared to the conventional liquid accelerator.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.5
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• pp.33-37
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• 2009

Hanji is a traditional Korean handmade paper, made of bast fibers of the paper mulberry. Its fiber furnish is much more expensive than wood fiber furnish. Hanji with a low basis weight requires additional opacity and smoothness for better writing and printing. Filler such as calcium carbonate can not be used to raise the opacity of Hanji because of its low retention in low basis weight paper and the high freeness of the Hanji fiber furnish. Addition of red algae pulp, which is prepared from marine red algae to the Hanji fiber furnish negated retention problems happening in the case of mineral filler addition, and produced a substantial improvement in the opacity and smoothness of Hanji. The higher retention was due to the much larger size of the red algae fibers compared to the mineral fillers. The improvement in opacity and smoothness were also due to the shape of the red algae fibers: that red algae fibers are narrower in widths and shorter in lengths than wood fibers results in increased surface area and smoothness.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.797-800
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• 2008

To decrease the usage of cement, the pozzolan reaction materials are used as a mineral admixture. Hwang Toh which is broadly deposited in Korea is well known as a environment friendly material and the activated Hwang Toh which has the property of pozzolan reaction is practically used as a mineral admixture of concrete. PET fiber which is made by recycled PET bottle controls micro crack in concrete. But the study about concrete mixed with reinforcing fiber is not enough and the property of Hwang Toh concrete mixed with PET fiber is more complicated case. So this study performed drying shrinkage experiment to analyse mechanical property of Hwang Toh concrete mixed with PET fiber.