• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1736-1745
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• 2002

The objective of this study is to predict the roll wear in hot rod rolling process. In this study hot rod rolling process for round and oval passes has been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the thermal softening of DCI (Ductile Cast Iron) roll according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering parameter curve. 3D wear program developed in this study might be used for adjusting the gap of rolls to set up a suitable rolling schedule for keeping dimensional tolerance of the product.

• Journal of the Korean Chemical Society
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• v.58 no.2
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• pp.205-209
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• 2014

Hematite iron oxide (${\alpha}$-$Fe_2O_3$) nanowalls were fabricated on aluminum substrate by a facile solvent-assisted hydrothermal oxidation process. The XRD and EDS patterns indicate that the sample has a rhombohedral phase of hematite $Fe_2O_3$. FE-SEM, TEM, HR-TEM, SA-ED were employed to characterize the resulting materials. $N_2$ adsorption-desorption isotherms was used to study a BET surface area. Their capability of catalytic degradation of titan yellow GR azo dye with air oxygen in aqueous solution over $Fe_2O_3$ catalysts was studied. The result indicates that the as-prepared product has a high catalytic activity, because it has a larger surface area. Langmuir and Freundlich isotherms of adsorption dye on the catalysts surface were investigated and the decomposition of titan yellow GR follows pseudo-first order kinetic.

• Fire Science and Engineering
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• v.30 no.4
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• pp.121-127
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• 2016

This study analyzed the structural and electrical characteristics of an iron fittings type Corrugated Stainless Steel Tubing (CSST) damaged by the Primary Current Injection Test System (PCITS). CSST consists of cladding, tube, nuts, clamp ring, flare cap, socket, and ball valve. For an evaluation of the dielectric withstand voltage, the area between the live part and non-live part of the CCST shall withstand a voltage of 220 V AC for one minute. For an evaluation of the insulation performance by 500 V DC, it is required that the insulation exceed more than $1M{\Omega}$ before the temperature rise test, $0.3M{\Omega}$ after the test. Although the average resistance of the product was $11.5m{\Omega}$, that of the product damaged at a current of 130 A by the PCITS was $11.50m{\Omega}$. Furthermore, parts of the cladding were melted and black smoke appeared when a current of 130 A applied for 10 s. After 60 s, most parts were heated and turned red. At 120 s, the parts that turned red had widened. Although it did not form a normal distribution because the P value was 0.019 with a confidential interval of 95%, it revealed outstanding characteristics with an AD (Anderson-Darling) value of 0.896 and a standard deviation of 0.5573.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.73-81
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• 2004

To develope of the inexpensive anti-stain chemicals, it was conducted to investigate the inhibitory effectiveness of mycelial growth and anti-mold effectiveness against test fungi causing surface mold of wood, iron corrosivity and hygroscopicity of six fluoride-based chemicals made from industrial by- product.Among the six chemicals. RNF-3 and RNF-4 were the most effective with respect to a mycelial growth control and anti-mold effectiveness. For the wood treatment with these chemicals, the optimum concentration was about 2% and there was no difference in the effectiveness of chemicals between wood species. The wood treated with synthesized chemicals showed a relatively high iron corrosion rate for corrosive F component whereas, in the treatment with RNF-3 and RNF-4, there was no difference from the untreated wood when the concentration was less than 2%. The hygroscopic property of wood was not effected by treatment of these chemicals. To prove the feasibility for practical using of RNF-3 and RNF-4 chemicals, it is necessary to test of anti-mold effectiveness in the sawmill by field test.

• Advances in environmental research
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• v.8 no.1
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• pp.55-69
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• 2019

The generation of ferrous slag, an industrial by-product from the iron ore industry, results in serious environmental problems. The chemical compositions indicate 30-34% SiO₂, 30-34% CaO, 18-22% Al₂O₃ and 0.5-0.6% Fe₂O₃. The specific gravity, moisture content and pH are in the range of 1.3-1.65, 9.1-10% and 8.5-9.0 respectively. The major part of the slag is composed of sand-size particles. The problems of disposal of slag could be minimized by considering its use in various environmental engineering applications providing additional value to the by-product. This paper mainly focuses on the potential utilization and valorisation of ferrous slag in both water and wastewater treatments. It is effective for the treatment of water and wastewater containing nutrients, heavy metals and polluted river/stormwater.

• Clean Technology
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• v.15 no.3
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• pp.194-201
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• 2009

Reductive reactivity of zero-valent iron nanoparticles was investigated for removal of nitrate-nitrogen which is considered one of the major water pollutants. To elucidate the difference in reactivity between preparation methods, iron nanoparticles were synthesized respectively from microemulsion and aqueous solution of ferric ions. Iron nanoparticles prepared from microemulsion were deposited on aluminum by electrophoretic method, and their reaction kinetics was compared to that of the same nanoparticles suspended in aqueous batch reaction. With an approximation of pseudo-first-order reaction, rate constants for suspended nanoparticles prepared from microemulsion and dilute aqueous solution were $3.49{\times}10^{-2}min^{-1}$ and $1.40{\times}10^{-2}min^{-1}$, respectively. Iron nanoparticles supported on aluminum showed ca. 30% less reaction rate in comparison with the identical nanoparticles in suspended state. However, supported nanoparticles showed the superior effectiveness in terms of nitrate-nitrogen removal per zero-valent iron input especially when excess amounts of nitrates were present. Iron nanoparticles deposited on aluminum maintained reductive reactivity for more than 3 hours, and produced nitrogen gas as a final reduction product of nitrate-nitrogen.

• Journal of environmental and Sanitary engineering
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• v.17 no.3
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• pp.14-20
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• 2002

In order to improve the quality and sensory evaluation of Fermented Soybean(Chungkugjang meju) were investigated. The samples were prepared and fermented by the inoculation of Bacillus strains (B. subtilis, number 1, B. natto, number 2) that the product made With sanitary canned food. 1. The water content of samples was 46.75~50.60%, pH 5.35~6.95 and total acidity 3.26~3.62. 2. The reducing sugar of content for sample was 9.49~10.05%, Amino-N, 67~396mg% and the activity of protease was 0.36~1.49unit/g. 3. The heavy metals analyzed from sample cans, iron, tin and lead content of sample were 5.32~5.84ppm, 27.31~29.04ppm and 0.019~0.021ppm. 4. Therefore, results that Chungkugjang-meju manufactured from B. natto starter induced better product Quality and sensory test than that of the B. subtilis strain.

• Journal of the Korean Ceramic Society
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• v.29 no.12
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• pp.942-948
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• 1992

Ultrafine iron oxide powder, {{{{ gamma }}-Fe2O3 and $\alpha$-Fe2O3, were prepared by the thermal decomposition of organometallic compounds. The formation process of powder includes the thermal decomposition and oxidation of the organometallic precursors, Fe(N2H3COO)2(N2H4)2 (A) and N2H5Fe(N2H3COO)3.H2O (B). The organometallic precursors, A and B, were synthesized by the reaction of ferrous ion with hydrazinocarboxylic acid, and characterized by quantitative analysis and infrared spectroscopy. The mechanistic study for the thermal decomposition was performed by DAT-TG. The iron oxide powder was obtained by the heat treatment of the precursors at 20$0^{\circ}C$ and $600^{\circ}C$ for half an hour in air. The phases of the resulting product were proved {{{{ gamma }}-Fe2O3 and $\alpha$-Fe2O3 respectively. The particle shape was equiaxial and the particle size was less than 0.1 ${\mu}{\textrm}{m}$. Magnetic properties of the {{{{ gamma }}-Fe2O3 powder obtained from A and B was 234 Oe of coercivity, 64.26 emu/g of saturation magnetization, 23.59 emu/g of remanent magnetization and 24.1 Oe, 47.27 emu/g, 3.118 emu/g respectively. The value of $\alpha$-Fe2O3 powder was 1.494 Oe, 0.4862 emu/g, 0.1832 emu/g and 1,276 Oe, 0.4854 emu/g, 0.1856 emu/g respectively.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.420-425
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• 2016

The present study aimed to calcium (Ca), iron (Fe) and zinc (Zn) contents were compared with reference values indicated on the nutrition label of nutrition emphasized food. Also, this paper will briefly review and evaluate what is currently known about Fe-Zn and Ca-Fe interaction. Ca, Fe or Zn-emphasized product, including cereal, snack, soy milk, chocolate product, other cocoa product, sugars product, beverage and tea were analyzed. The contents of Ca, Fe, and Zn in samples after dry-ashing were examined by ICP. The measured Ca (n = 42), Fe (n = 13), Zn (n = 6) values were ranged 87~176%, 98~167%, 98~275% of reference value indicated product, respectively. All samples were ranged more than 80% of the reference value, which were complied with food regulation. High intake of Ca has been shown to adversely affect Fe absorption and the negative effect of Fe on Zn absorption is well known. Therefore, it is important to consider Ca-Fe and Fe-Zn absorption interaction, when Ca, Fe or Zn-emphasized product produce and nutrition labeling policy should be managed regularly with continuous monitoring.

• Journal of the Korean Ceramic Society
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• v.28 no.12
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• pp.996-1004
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• 1991

In this study, we tried to synthesis iron hydroxide suitable for longitudinal magnetic recording media from waste acid, which is a by-product of an iron works factory. Effects of initial pH of reactants, reaction temperature, reaction time for the synthesis of acicular iron hydroxide were studied in relation to particle properties of iron hydroxide and magnetic properties of maghemite powders. As the pH in reactant solution increased, $\beta$-FeOOH(pH=4.5), mixture of $\beta$-FeOOH and $\alpha$-FeOOH(4.5$\alpha$-FeOOH and Fe3O4(6.4$\alpha$-FeOOH (pH>13) was found to from in order. Especially, $\alpha$-FeOOH formed above pH 13 was single phase with superior acicularity. The temperature range over which the single-phase goethite can be formed increased as the initial pH of reactants increased (pH 13:10~5$0^{\circ}C$, pH 13.2:10~7$0^{\circ}C$, pH 13.5:0~8$0^{\circ}C$). The goethite formed between 40~6$0^{\circ}C$ has superior characteristics because the acicularity increased with increasing temperature but at high temperature (>6$0^{\circ}C$) Fe3O4 (pH=13) was found to start to form. Generally, single phase of goethite was found to form after one hour when an optimized condition. The particle size of goethite did not change as the reaction time increased over one hour. Accordingly, the magnetic properties of ${\gamma}$-Fe2O3 produced from goethite were not altered.