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Kashihara M.,Mori Seiki Co. | Suzuki S.,Osaka University | Suzuki S.,Waseda University | Kawamura Y.,Osaka University | And 5 more authors.
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2010

Lotus-type porous carbon steel slabs with long cylindrical pores aligned in one direction were fabricated by the continuous casting technique in a mixture gas of N2 0.8 MPa and Ar 1.7 MPa or in N2 2.5 MPa at various transfer velocities from 2.5 mm•min-1 to 20 mm•min-1. The pore size in lotus carbon steel fabricated in the mixture gas of nitrogen and argon was small and homogeneous, whereas the pore size in nitrogen had bimodal distribution depending on the transfer velocity. The large pores were observed mainly at the edge of the slab, which are considered to be merged of several inclined pores. The porosity depended on nitrogen partial pressure, which is explained by Sieverts' law. The hardness of lotus carbon steel matrix increased, which was attributed to the solid-solution of nitrogen. © 2010 The Minerals, Metals & Materials Society and ASM International.

Jung S.,University of Tokyo | Dodbiba G.,University of Tokyo | Chae S.H.,Korea Industrial Complex Corporation | Fujita T.,University of Tokyo
Journal of Cleaner Production | Year: 2013

This paper presents a novel approach using discounted cash flow (DCF) and multi-attribute global inference of quality (MAGIQ) methods to evaluate the economic, environmental, and social performances of eco-industrial park (EIP) pilot projects. As a test case, we evaluated South Korean EIP pilot projects that primarily focus on the development of industrial symbiosis networks in existing industrial complexes. The results demonstrated that networks with high initial investment or higher value-added products tend to have high economic performance. Additionally, several projects involving energy networks have resulted in high positive environmental performance through greenhouse gas emissions mitigation. Waste acid/alkali solution recycling projects also showed remarkable social outcomes on account of the variety of networks formed and active participation from enterprises. The present approach incorporating the DCF and MAGIQ methods provides a simple and promising decision-making tool for quantitative performance evaluation of EIP pilot projects. Furthermore, valuable lessons from the evaluation considering economic, environmental, and social performances will provide the basis for future EIP establishment. © 2012 Elsevier Ltd. All rights reserved.

Jung S.C.,Sunchon National University | Cho H.C.,Sunchon National University | Ra D.G.,Sunchon National University | Park S.H.,Sunchon National University | And 3 more authors.
Water Science and Technology | Year: 2011

In this study, zero-valent iron (ZVI) was produced using iron oxide that is a by-product of a pickling line at a steel works. The reaction activity of the produced ZVI was evaluated through a series of decomposition experiments of Orange II aqueous solution. The size of ZVI particles increased with reduction temperature due to coalescence. Correspondingly, the specific surface area of ZVI decreased with increasing reduction temperature. The decomposition efficiency of synthesized ZVI particles was higher at a lower pH. In particular, no significant decomposition reaction was observed at pH of 4 and higher. The rate of the ZVI-assisted decomposition of Orange II was increased by addition of H 2O 2 at pH of 3, whereas it was reduced by addition of H 2O 2 at a higher pH of 6. Nevertheless, simultaneous use of ZVI, UV and H 2O 2 led to a considerable increase in the decomposition rate even at a high pH condition (pH = 6). © IWA Publishing 2011.

Kim S.,Doosan Heavy Industries and Construction | Kim J.,Korea Industrial Complex Corporation | Seo G.,Changwon National University
Desalination and Water Treatment | Year: 2013

A novel powder-activated carbon (PAC) by surface modification with iron oxide nanoparticles was applied to microfilter (MF) membrane system for stable operation and removal of natural organic matter (NOM) in water. Two types of PAC (wood-based and coal-based) were used for the preparation of the iron oxide nanoparticle-impregnated PAC (IPAC). The impregnation of the iron oxide nanoparticles played a role to increase the pHPZC of the PACs which means that the IPAC has higher basicity and larger adsorption capacity than the virgin PAC. From the experimental results of size exclusion chromatography (SEC) and SUVA254, there was no specific selectivity in adsorption of NOM on the IPAC. The saturated magnetization value of the IPAC was in the range of 6.75-8.04 emu/g that was enough to separate the IPAC particle from aqueous solution by magnetic force. An IPAC column followed by MF membrane system was operated to investigate NOM removal and membrane fouling control. A magnetic ring on the column above the IPAC bed surface could effectively hold the overflowing discrete IPAC particles. The system performance was compared with other similar MF membrane systems (PAC column-MF, high concentration PAC-MF (HCPAC-MF),and single MF) in terms of trans-membrane pressure (TMP) increase and NOM removal. For a 30-day operation, TMP of the MF membrane system could be maintained stably at 13 kPa with the IPAC column pretreatment, while the TMP of other membrane systems increased to the operation limit (40 kPa). Dissolved organic compound (DOC) and UV254 removal by the IPAC-MF system were 85.3 and 79.6%, respectively. And the removal efficiency of turbidity was more than 80%. With similar removal efficiency of DOC and UV254, the IPAC-MF process showed much more stable operation for longer periods compared to the other hybrid MF membrane systems (HCPAC-MF and PAC column-MF). © 2013 Copyright Balaban Desalination Publications.

Lee H.,Sunchon National University | Park S.H.,Sunchon National University | Kim S.J.,Sejong University | Kim B.H.,Chosun University | And 3 more authors.
Progress in Organic Coatings | Year: 2012

The preparation of TiO 2 photo-catalyst films on alumina balls via low pressure metal organic chemical vapor deposition using titanium tetraisopropoxide and their photo-catalytic activity in bromothymol blue (BTB) decomposition using a microwave/UV/TiO 2 photo-catalyst combined process system were investigated. The results indicate that the film structure strongly depended on the reaction temperature. Among the grown TiO 2 films, anatase and rutile showed high photo-catalytic activities, whereas amorphous TiO 2 films showed lower activities. The BTB decomposition rate increased with the microwave intensity and ozone injection rate. A significant synergistic effect was observed when hydrogen peroxide addition was combined with other elemental techniques. © 2011 Elsevier B.V.

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