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목질계 바이오매스 연소부산물 분석과 모르타르 혼입 평가
정영동 ( Jung Young-dong ),김민수 ( Kim Min-soo ),박원준 ( Park Won-jun ) 한국건축시공학회 2023 한국건축시공학회지 Vol.23 No.6
This research experimentally evaluated the recyclability of four varieties of lignocellulosic fly ash(FA), a by-product from three power plants employing lignocellulosic biomass(Bio-SRF, wood pellets) as a fuel source. Comprehensive analyses were conducted on FA, encompassing both physical parameters (particle shape, size distribution, fineness, and density) and chemical properties(chemical composition and heavy metal content). Mortar test specimens, with FA mixing ratios ranging from 5 to 20%, were produced in compliance with KS L 5405 standards, and their flow and compressive strength were subsequently measured. The test results indicated that the four types of FA exhibited particle sizes approximately between 20~30μm, densities around 2.3~2.5g/cm<sup>3</sup>, and a fineness range of 2,600~ 4,900cm<sup>2</sup>/g. The FA comprised approximately 50~90% of components such as SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, and CaO, displaying characteristics akin to type-II and type-III FA of KS L 5405 standards, albeit with differences in chlorine and SiO2 content. From the mortar tests, it was observed that the compressive strength of the mortar ranged between 34~47MPa when the pellet combustion FA was mixed in proportions of 5~20%. FA, produced exclusively from the combustion of 100% lignocellulosic fuel, is assessed to possess high recyclability potential as a substitute for conventional admixtures.
경주 월산리 신라 고분군 출토 단조철기에 나타난 철기기술
정영동 ( Young Dong Jung ),정원섭 ( Won Seop Jung ),최광진 ( Kwang Jin Choi ),박장식 ( Jang Sik Park ) 대한금속재료학회 ( 구 대한금속학회 ) 2006 대한금속·재료학회지 Vol.44 No.5
This work has metallographically examined three forged iron artifacts from the Wolsanni tomb complex constructed by Silla, and identified a pattern in the engineering sequences applied in their manufacture. The specific distribution of such phases as martensite, pearlite and ferrite consistently observed in their microstructure shows that the artifacts were manufactured in a sequence of shape-forging followed by steel-making. This is unique in that shape-forging comes before steel-making as opposed to another sequence where shape-forging comes after steel-making. The choice between these two, determined by the nature of available steel-making and iron-smelting processes, apparently played a crucial role in characterizing a local iron industry in ancient Korea. This article will compare the Wolsanni results with those of the Hwangnam Great Tomb of Silla and the Kaya tomb complex at Daeseongdong, Kimhae, and will propose that Silla and Kaya had developed a similar iron industry based on the production of low C iron and the particular steel-making by carburization. The invention of special iron artifacts named Cheoljeong must have been a necessary requirement for such unique iron technology to be successfully established.