• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.173.1-173.1
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• 2011

The high fuel flexibility of gas turbine power system has boosted their use in a wide variety of applications. Recently, the demand for biogas generated from the digestion of organic wastes and sewage waste water as a fuel for gas turbines has increased. We investigated the performance of high pressure biogas compression system and operating conditions for supplying biogas. The total flow per minute of biogas from food waste water digestion tank is $54Nm^3$. The main type of biogas compression system is the reciprocating system and screw type system. The target of biogas mechanical data is the as belows; inlet pressure 0.045bar, supplying biogas temperature is $30{\sim}60^{\circ}C$, and final pressure is above the 25 bar. Also, inlet conditions of biogas consist of CH4 48.5%~83%, $H_2S$ Max. 500ppm, $NH_3$ Max. 1,500ppm and Siloxane 2.7~4.6ppm. The boosting Blower system raises a pressure from 0.045bar to 1bar before main compressor. The main system lay out of reciprocating consisits of compressor driver, filter, cooling system, blowdown vessel, control system and ESD(Emergency Shut Down) system. And an enclosure package needs to be installed for reducing noise up to 75dB. The system driver is the electronic motor of explosion proof type. Forthe compressor system reliable operation, the cleaning system something like particulate filter needs to be set up in the inlet of compressor and Coalescing Filter in the outlet of compressor. Particulate Filter has to be removed above $10{\mu}m$ size of the particles in biogas. The coalescing filter(Micofine Borosilicate Glass Fibers Filter treated phenol acid) also removes moisture and oil of above $0.3{\mu}m$ to be involved in high pressure biogas up to 90%~98%.

• Textile Coloration and Finishing
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• v.1 no.1
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• pp.54-62
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• 1989

The woven fabric composed of nylon 6 filaments was treated with aqueous solutions (20, 30, 40, 50, 60%) of formic acid at 3$0^{\circ}C$ for 10 minutes under unrestrained condition, and the shrinkage behavior and some kinds of properties were examined. The shrinkages of the constituent yarns and fabric were increased with formic acid concentration, but they were lower than that of the original filaments because of fabric-structural factors. And the shrinkage of the warp was lower than that of the weft because of the residual stress from weaving process. By the restraint forces such as fabric-structural factors and residual stress, the constituent filaments were damaged partially at 60% of formic acid concentration and the degree of damage on the warp was greater than on the weft. And though the fabric count were increased overall, the spacing between the warps was decreased prior to the weft and eliminated nearly at 60% of formic acid concentration. The thickness, tensile strength, elongation, and handle value of fabric were increased overall with formic acid concentration excepting that the tensile strength for both the warp and weft directions and the elongation for the warp direction were decreased instead by the damage of yarns. But the crease recovery was decreased except the case of the weft direction at 60% of formic acid concentration.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.299-308
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• 2000

This study analyzed solid wastes generated from a school. The emission potential of hazardous pollutants generated from incineration of the school solid wastes (SSWs) was analyzed. Components of the SSWs were identified and the SSWs were classified into combustible and non-combustible wasts. The combustible wastes consisted of papers of 56.5^ plastics of 30.2% woods of 7.1% and fibers of 6.1% based on weight of the wastes. The moisture content and the ash content of the combustible wastes were 18~20% and 11~13% respectively. The combustible wastes of the SSWs were incinerated by using a small-scale incinerator. Fly and bottom ashes and volatile organic compounds (VOCs) were collected from the incineration. Also the metal leaching experiments on the fly and bottom ashes were performed, In analysis of metals leached from the ashes the total amounts of metals leached in the acid solution (pH=3) were much greater than those in the neutral solution (pH=5.8~6.2) For the same amounts of the fly and bottom ashes the total amounts of metals leached from the fly ashes were much greater than those from the bottom ashes. The VOCs produced from incineration of the SSWs consisted of aromatics of 42.1% aliphatic alkenes of 26.3% oxidized forms of 17.3% and aliphatic alkanes of 14.3% In addition the considerable amounts of hazardous air pollutants (e.g benzene chloro-benzene and chloro-alkanes) and compounds (e. g, aliphatic alkenes) with high potential of ozone or photochemical smog formation were identified from the incineration experiment of the SSWs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1239-1244
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• 2014

In this study, two fiber-optic sensors were fabricated to measure water level and temperature using optical fibers, a coupler, a Lophine and an OTDR (optical time-domain reflectometer). First, using Fresnel's reflection generated at the distal-ends of each optical fiber, which was installed at different depth, we measured the water level according to the variation of water level. Next, we also measured the temperature of water using a temperature sensing probe based on the Lophine, whose absorbance changes with the temperature. The measurable temperature range of the fiber-optic sensor is from $5^{\circ}C$ to $65^{\circ}C$ because the maximum operation temperature of the optical fiber without a physical deterioration is up to $80^{\circ}C$.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.405-409
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• 2006

Bokbunja (Rubus coreanus Miquel) is a wild berry belonging to Rosaceae genus of which application areas have been expanded due to many health effects. Bokbunja berry contains carbohydrates, protein, fats and dietary fibers as major components and various flavonoids such as tannins, volatile components including organic acids, alcohols and hydrocarbons as minor ones. Those active compounds attribute to the following health effects: increase in immune function and antioxidant activity, rise in hormone secretion, suppression of the growth of type B hepatitis virus, and control of weight gain. To utilize the above activities, many products have been developed by using Bokbunja berry extracts in the area of foods, liquors, and cosmetics. Recently, pure compounds have been isolated from the extracts for the development of medicines. In this mini review, the state-of-the-art of Bokbunja researches and applications including papers and patents is summarized.

• Carbon letters
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• v.16 no.3
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• pp.147-170
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• 2015

In recent decades, there has been an increasing interest in the use of carbon fiber reinforced plastic (CFRP) in aerospace, renewable energy and other industries, due to its low weight and relatively good mechanical properties compared with traditional metals. However, due to the high cost of petroleum-based precursors and their associated processing costs, CF remains a specialty product and as such has been limited to use in high-end aerospace, sporting goods, automotive, and specialist industrial applications. The high cost of CF is a problem in various applications and the use of CFRP has been impeded by the high cost of CF in various applications. This paper presents an overview of research related to the fabrication of low cost CF using polyethylene (PE) control technology, and identifies areas requiring additional research and development. It critically reviews the results of cross-linked PE control technology studies, and the development of promising control technologies, including acid, peroxide, radiation and silane cross-linking methods.

• Journal of the Korean Society of Costume
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• v.65 no.7
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• pp.47-59
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• 2015

This paper studies the conservation treatment of Lady Shim's costume, which was excavated in Jecheon Province in 2012. There were the significant problems, which were encountered in the treatment of the costume ; First the Jeogoris were transformed during the excavation, Second fibers were seriously deteriorated, Third most of the fabrics such as Chusa were readily deformed. To overcome these problems and to secure stability in the conservation treatment, we decided to alternate between two different washing methods ; dry cleaning by n-hexane and wet cleaning by water. The costume shape was recovered by steaming and by swelling with Hanji(Korean traditional paper). The combined cleaning method proved to be relatively efficient and stable. In addition, the shape of Chusa was well preserved by dry cleaning.(using n-hexane also solved the problem of bad smell after washing with organic solvents.) The effects of the conservation treatment on the excavated costumes could be seen in the change of Lab color difference. Washing made the distribution of Lab color difference narrower, which may suggest that the impurities on the fiber was removed by washing. In addition, the value of L was greater than a-value and b-value after the treatment. This result indicates that the change of value represents the change of color difference by cleaning.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.163-171
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• 2014

Environmental issues about indoor air quality have been increased and focused on volatile organic compounds (VOCs) caused cancer, asthma, and skin disease. Reducing VOCs has been attempted in many different methods such as using environmentally friendly materials and air cleaner or purifier. Charcoal is well known material for absorbing VOCs. Therefore, carbonized board from medium density fiberboard has been developed. We assumed that the source of carbonized boards can be any type of wood-based panels. In this study, carbonized boards were manufactured from oriented strand board (OSB) at 400, 600, 800, and $1000^{\circ}C$. Each carbonized OSB (c-OSB) was evaluated and determined physiomechanical characteristics such as exterior defects, dimensional shrinkage, modulus of elasticity, and bending strength. No external defects were observed on c-OSBs at all carbonizing conditions. As carbonizing temperature increased, less porosity between carbonized wood fibers was observed by SEM analysis. The higher rate of dimensional shrinkage was observed on c-OSB at $1000^{\circ}C$ (66%) than c-OSB at 400, 600, and $800^{\circ}C$ (47%, 58%, and 63%, respectively). The densities of c-OSBs were lower than original OSB, but there was no significant different among the c-OSBs. The bending strength of c-OSB increased 1.58 MPa (c-OSB at $400^{\circ}C$) to 8.03 MPa (c-OSB at $1000^{\circ}C$) as carbonization temperature increased. Carbonization temperature above $800^{\circ}C$ yielded higher bonding strength than that of gypsum board (4.6 MPa). In conclusion, c-OSB may be used in sealing and wall for decorating purpose without additional artwork compare to c-MDF which has smooth surface.

• Applied Chemistry for Engineering
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• v.23 no.4
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• pp.367-371
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• 2012

Waste printed circuit boards (WPCBs) contain valuable metals such as Cu, Ni, Au, Ag, and Pd. For an effective recycling of WPCBs, it is essential to recover the valuable metals. In recent years, recycling processes have come to be necessary for separating noble metals from WPCBs due to an increasing amount of electronic device wastes. However, it is well known that glass reinforced epoxy resins in the WPCBs are difficult materials to separate into elemental components, namely metals, glass fibers and epoxy resins in the chemical recycling process. $K_3PO_4$ as a catalyst in dimethylformamide (DMF) and N-Methyl-2-pyrrolidone (NMP) was used to depolymerize epoxy resins for recovering metallic and non-metallic components from WPCBs. Reactions of WPCBs were carried out at temperatures $160{\sim}200^{\circ}C$ for 2~12 h. The recycled glass fiber from WPCBs was analyzed by thermogravimetric analyzer (TGA) and evaluated the degree of solubility of the epoxy resin for separation efficiencies of the WPCBs.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.16-21
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• 2016

Carbon Fiber Reinforced Plastic(CFRP) composite with a higher specific strength and rigidity is more excellent than conventional metallic materials or other organic polymer of FRP. It has been widely used in vehicles, aerospaces and high technology industries which are associated with nuclear power fields. However, CFRP laminated composite has several disadvantages as like a delamination, matrix brittleness and anisotropic fibers that are the weak points of the crack initiation. In this present work, the reinforced silicon carbide(SiC) particles were added to the interlayer of CFRP laminates in order to mitigate the physical vulnerability affecting the cracking and breaking of the matrix in the CFRP laminated composite because of excellent specific strength and thermal shock resistance characteristics of SiC. The 1wt% of SiC particles were spread into the CFRP prepreg by using a spray coating method. After that, CFRP prepregs were laminated for the specimen. Also, the twill woven type CFRP prepreg was used because it has excellent workability. Thus the mechanical and fracture behaviors of the twill woven CFRP laminated composite reinforced with SiC particles were investigated with the acoustic emission(AE) method under a fracture test. The results show that the SiC particles enhance the mechanical and fracture characteristics of the twill CFRP laminate composite.