• Journal of the Korean Wood Science and Technology
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• v.50 no.2
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• pp.104-112
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• 2022

Indoor air quality is a very important environmental factor in modern society. However, air pollutants generated from various interior construction materials significantly affect the human body, including formaldehyde (HCHO) and volatile organic compounds that threaten public health by deteriorating indoor air quality. Effective in removing these harmful substances are porous materials, such as woodceramics. In this study, charcoal, a porous material, was added to rice husk, an agricultural by-product, and sawdust generated during the sawing process to prepare boards and ceramics at different mixing ratios, and the HCHO deodorization performance and far-infrared emission characteristics were measured. As the mixing ratio of charcoal increased, the deodorization rate of the boards and ceramics tended to increase. Overall, the deodorization rate was measured to be 80% to 90%, indicating that the boards and ceramics prepared with charcoal are suitable to be used for the purpose of deodorization. The effect of the material mixing ratio on far-infrared emissivity and emission power was insignificant.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.13-19
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• 1989

Two different quartz types of gasification reactor were used for pyrolysis and gasification of sawdust, ricestraw, ricehusk and municipal wastes which contain only cellulosics., operating at 1 atmospheric and vacuum pressure respectively. Also a stainless steel autoclave gasification reactor was used which is possible to use up to 100 atmospheric pressures and $800^{\circ}C$ of reaction temperature to complete pyrolysis and gasification reaction. The catalysts used in this reaction w- ere $K_2CO_3$, $Na_2CO_3$, Ni and Ni-$K_2CO_3$ as CO-Catalyst. The product gas mixtures were identified to be CO, $CO_2$, $C_3H_3$, $CH_4$ and $CH_3CHO$ etc. by Gas Chromatography and Mass Spectrometry. The pressurized gasification reaction shows significant increase in terms of methane composition and yield of product gases, comparing with those from unpressurized gasification reactions. The total volume of product gas mixtures amounts to 1600-1800ml per1gof waste of waste lignocellulosics or municipal waste, and the metane content of the gas mixtures reached to 40%, when $800^{\circ}C$ of reaction temperature and 100 atmospheric pressures with Ni-$K_2CO_3$ as CO-catalyst in the pressurized gasification reaction were used. This results show that the product gas mixtures containing 40% of methane call be used for alternative enegy source.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.185-185
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• 1998

As part of our continuing attempts to evaluate biologically active compounds from fruiting bodies of cultivated fungus of Paecilomyces japonicus Yasuda, we conducted series of experiments on various fractions and compounds isolated by systematic fractionations. Our main efforts were concentrated on searching for compounds showing antitumor activities, which were tested on mice carrying Sarcoma-180 ascitic tumor. The antitumor activity was assessed by the life spans after these mice were administered Lp. with test compounds for consecutive 20 days. One of two pure compounds, which we have isolated to date, demonstrated significant prolongation of life span. ( Mean Survival Time: 30.3 days compared to that of control: 23.6 days). Structural analysis showed that this compound corresponds to D-mannitol. On the other hand, Ergosterol, another isolated pure compound didn't show efficient antitumor activity. We also obtained water-soluble fractions containing protein-bound polysaccharides and n-butantol fractions, which showed strong antitumor activities, 35.4(150%) and 32.1(136.0%) days of MST, respectively. In SRB assay, however, the test materials didn't show any toxic effects, but the level of acid phosphatase increased significantly when they were applied in cultured macrophage in vitro. Therefore, we concluded that antitumour activities might be attributed to immunostimulating rather than cytotoxic effects. Further experiments are underway to purify and structurally characterize new antitumour compounds from the active fractions.

• Transactions of Materials Processing
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• v.25 no.4
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• pp.268-274
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• 2016

In the automotive seat industry, the use of a fine blanking press is important for manufacturing of high precision products. Among them, a gear part which is a main component of an automotive seat recliner is generally manufactured by fine blanking press. However, the use of conventional mechanical press has been increasing in manufacture of gear part because of low productivity of fine blanking press. In this study, new forming process is suggested to fabricate the gear part with high precision by using mechanical press. The effect of flow restriction die (FRD) which has the restriction of blank edge on dimensional accuracy is investigated by FE-analysis. FE-analysis results for different conditions of FRD indicated that FRD has high dimensional accuracy with the lowest roll-over and the highest perpendicularity of gear part. After application to fabrication of the gear part using mechanical press, the measured dimensional characteristic was compared with the required specification of final product. In addition, results of the performance test showed that the product fabricated by developed process satisfied the required strength and durability. The results show that the suggested forming process by using FRD and mechanical press can replace fine blanking on the viewpoint of dimensional accuracy and productivity.

• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.35-42
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• 2017

In this study, the effect of electrolyte addition on the removal of organics and nutrients in electrochemical wastewater using a copper electrode, and the characteristics of the by-product of electrolysis were investigated. The removal of organics increased significantly as shorter reaction times upon the addition of chloride ion, and most of the electrolysis reaction was completed within 20 min. The reaction rate gradually increased in proportion to the $Cl^-$/COD ratio, whereas the highest removed mass of organic matter per mass of added electrolyte was observed at a $Cl^-$/COD ratio of 1. After the addition of electrolyte, significant removal of ammoniacal nitrogen was observed as a result of the enhanced generation of oxidizers such as hypochlorite. Excellent phosphorus removal was also achieved in a very short reaction time (within 2 min) by electro-coagulation. As the electrolysis progressed, the amount of by-product increased gradually, whereas a decrease of sludge volume index was observed after the addition of electrolyte. This indicated that the settling performance of the by-products was better, and their removal would be easily achieved.

• Structural Engineering and Mechanics
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• v.92 no.1
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• pp.89-97
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• 2024

Discarded cigarette butts in the environment have caused significant pollution. Therefore, providing solutions to address these environmental issues is of great importance. Concrete is known as one of the most widely used materials around the world. Hence, this study investigates the feasibility of using cigarette butts to product concrete. For this purpose, cellulose acetate fibers obtained from cigarette butt filters were added to silica fume concrete in 10 different volume ratios. Then, the mechanical properties of the concrete samples, including compressive strength, Brazilian tensile strength, and flexural tensile strength, were examined. Based on the results, adding fibers to silica fume concrete improved the mechanical properties of the concrete. Among the 10 mixing designs, adding 0.2% by volume of fibers to silica fume concrete yielded the highest compressive and tensile strengths. In other words, adding 0.2% by volume of fibers resulted in a 16% and 34% increase in compressive strength and a 70% and 38% increase in Brazilian tensile strength at 7 and 28 days, respectively, compared to the state without cellulose acetate fibers. Additionally, the flexural tensile stress capacity increased by 56%. Furthermore, the vertical deformation tolerance in beam specimens increased by 287%, and the energy absorption capacity of the concrete beam also significantly increased. Consequently, along with the significant improvement in the mechanical properties of concrete, this study proposes a new and practicalstrategy to addressthe environmental issues caused by waste cigarette butts.

• Korean Journal of Materials Research
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• v.12 no.3
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• pp.176-181
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• 2002

Fabrication of ${\beta}-FeSi_2$ was attempted by making use of the combined process of mechanical alloying (MA) and spark plasma sintering (SPS). MA was performed under the Ar gas atmosphere using mixed powders of pure iron and silicon having the mole fraction of 1:2. SPS process was performed at 800-85$0^{\circ}C$ with the applied pressure of 50MPa and the holding time was ranging from 0 to 30min. The mechanically alloyed powder by cyclic operation of rotor for 15hrs consisted of $\varepsilon$-FeSi and Si phases. When this mechanically alloyed powder was sintered by SPS process above 85$0^{\circ}C$, $\varepsilon$-FeSi and ${\alpha}-Fe_2Si_5$ phase were formed. Bulk product sintered at 82$0^{\circ}C$ for 30min consisted of ${beta}-FeSi_2$ phase with a small fraction of $\varepsilon$-FeSi and the density of sintered specimen was 75.3% theoretical density. It was considered that the MA/SPS combined process was effective for the preparation of ${\beta}-FeSi_2$ without heat treatment process after sintering.

• Journal of Soil and Groundwater Environment
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• v.21 no.2
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• pp.1-7
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• 2016

Ferrous slag is a by-product from steel making process and waste concrete is generated from construction activities. Large part of ferrous slag and waste concrete are recycled as construction materials. However, Ca²⁺ leaching out of ferrous slag and waste concrete in the water-contacting environment can cause a strength change. Strength can be reduced due to the dissolution of solid form of CaO which is one of the main contents of ferrous slag and waste concrete. On the other hand, strength can be enhanced due to the pozzolanic reaction of cementitious components with water. In this study, steelmaking slag, blast furnace slag, and waste concrete were aged by exposure to raining events, and the change of their compaction and shear strength characteristics was investigated. Optimum moisture content of all materials used in this study increased with aging period while maximum dry unit weight slightly decreased, implying that the relative contents of fine particles increased as the CaO solid particles were dissolved. Internal friction angle and shear strength of recycled materials also increased with aging period, indicating that the materials became denser by the decrease of void ratio attributed to the fine particles generated during the weathering process and the development of cementitious compounds increasing the bonding and interlocking forces between the particles. The results of this study demonstrated that mechanical strength of recycled materials used as construction materials has little chance to be deteriorated during their service life.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.1
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• pp.58-66
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• 2013

This study investigated quality properties of alkali activated cement free mortar using industrial by-product such as cement kiln dust(CKD), silica fume(SF) and quartz sand powder(SP) to compare with previous research about blast furnace slag(BS) and fly ash(FA). The results were as following. All materials were effective to increase compressive strength, however they showed different tendency on flowability. CKD and SP increased flowability, but on the other hand SF did not because it's blain was great difference with other materials. Flowability and compressive strength were related with grading distributions of binders because CKD, SP and SF which had small particle size filled up BS and FA. Application of industrial by-products with various grading distributions could be effective for the high early strength and flowability of alkali activated cement free mortar using BS.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.7
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• pp.1111-1120
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• 2013

Zizania latifola has used for folk medicine in Korea. It is effective in treating skin trouble and sensitivity skins. The purpose of this study was to develop high valuable types of bath preparation of Zizania latifolia. The natural materials were manufactured by the mixed ratio of Zizania latifolia. Product was manufactured by the mixed ratio of Zizania latifolia and 3 natural materials. Green tea was highest in sensory evaluation as similar with Zizania latifolia. optimum condition of mixed ratio was adaptive 50% Houttuynia cordata, 30% green tea with 20% Artemisia vularis. Product's sensory evaluation was showed best in mixing 40% and Zizania latifolia extract 60%. There were optimal condition for manufacturing of cleansing. Therefore, The development of a bath preparation used by Zizania latifolia is very useful for manufacturing cleansing. We suggest that it help for improve skin trouble and make healthy skin.