• Microbiology and Biotechnology Letters
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• v.25 no.6
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• pp.552-559
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• 1997

Fe (III) impurities in clay could be microbially removed by inhabitant dissimilatory Fe (III) reducing microorganisms. Insoluble Fe (III) in clay particles was leached out as soluble reductive form, Fe (II). The microorganisms removed from 10 to 45% of the initial Fe (III) when each sugar was supplemented to be in ranges of 1 - 5 % (w/w; sugar/clay). The microorganisms reduced 2.1 - 12.8 mol of Fe (III) per 100 mol of carbon in sugars metabolized when sugars such as glucose, maltose, and sucrose were used as sole carbon source. Bacillus sp. IRB-W and Pseudomonas sp. IRB-Y were isolated from the enrichment culture of the clay. The isolates were considered to participate in metabolizing organic compounds to fermentative intermediates with relatively little Fe (III) reduction at initial Fe (III) reduction process. By the microbial treatment, the whiteness of the clay was increased form 63.20 to 79.64, whereas the redness was obviously decreased form 13.47 to 3.55. This treatment did not cause any unfavorable modifications in mineralogical compositions of the clay.

• Resources Recycling
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• v.4 no.1
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• pp.60-68
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• 1995

Iron-bearing dust which stems from steelworks were pelletized and bonded with portland cement in order to attempt to use for blast iurnace burdens. The characterist~cs of cold bonded dust pellet were investigated. It was found that the compression strength of cold bonded pellet contaning portland cement of 10 wt.% reached above 150kg/p by proper curing treatment. Direcl contad of carbon with iron oxides seems to greately enhance a reduction reaction and herewxth increased chances to lorn pores at high temperature environment. Tumbler strength, RDI, and swelling of cold bonded pellet were similiar to and/or better than those of iron ore sinter and fired pellet.

• Journal of the Korean GEO-environmental Society
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• v.8 no.2
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• pp.41-48
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• 2007

Zevo-valent iron (ZVI) has been widely used in permeable reactive barriers for reducing organic contaminants, such as trichloroethylene (TCE). The rapid reaction time, however, leads to decrease in reactivity and availability of ZVI. Shewanella algae BrY, a strain of dissimilatory iron reducing bacteria, can reduce the oxidized Fe (III) to Fe (II) and reduced Fe (II) can be reused to reduce the contaminant. The effect of Shewanella algae BrY on the reduction of the oxidized ZVI column and further TCE removal in the contaminated groundwater were studied at different flow rates and TCE input concentrations in this study. High input concentration of TCE and flow rate increase the amount of input contaminant and make to lower the effect of reduction by Shewanella algae BrY. Specially, the fast flow rate inhibits the direct contact and implantation on the surface of iron. The reduction of oxidized iron reactive barrier by Shewanella algae BrY can decrease the decreation of duration of PRBs by the precipitation of oxidized iron produced by dechlorination of TCE.

• Journal of Microbiology
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• v.39 no.3
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• pp.149-153
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• 2001

The electron transfer reaction is one of the most essential processes of life. Not only does it provide the means of transforming solar and chemical energy into a utilizable form for all living organisms, it also extends into a range of metabolic processes that support the life of a cell. Thus, it is of great interest to understand the physical basis of the rates and reduction potentials of these reactions. To identify the major determinants of reduction potentials in redox proteins, we have chosen the simplest electron transfer protein, rubredoxin, a small (52-54 residue) iron-sulfur protein family, widely distributed in bacteria and archaea. Rubredoxins can be grouped into two classes based on the correlation of their reduction potentials with the identity of residue 44; those with Ala44 (ex: Pyrococcus furiosus) have reduction potentials that are ∼50 mV higher than those with Va144 (ex: Clostridium pasteurianum). Based on the crystal structures of rubredoxins from C. pasteurianum and P. furiosus, we propose the identity of residue 44 alone determines the reduction potential by the orientation of the electric dipole moment of the peptide bond between 43 and 44. Based on 1.5 $\AA$ resolution crystal structures and molecular dynamics simulations of oxidized and reduced rubredoxins from C. pasteurianum, the structural rearrangements upon reduction suggest specific mechanisms by which electron transfer reactions of rubredoxin should be facilitated.

• Journal of Nutrition and Health
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• v.5 no.2
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• pp.91-103
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• 1972

Zinc is one of the essential trace elements in the living organism for growth and health. The first identified metalloenzyme, carbonic anhydrase, is a zinc compound and several others have been described since. Among zinc deficiency syndromes in animals porcine parakeratosis has been successfully treated with zinc supplements, and in man a syndrome of anemia, hypogonadism, hepatosplenomegaly, and dwarfism, prevalent in parts of Iran and Egypt, has been ascribed to lack of zinc in the diet. Dietary zinc excess in the rat is manifested by a hypochromic, microcytic anemia, poor growth, reduction in liver catalase and cytochrome oxidase. The present study is an attempt to delineate the changes of tissue contents of trace elements, especially of iron, copper and zinc in liver and kidneys of the rats. Weanling albino rats, weighing 60 to 80gm. were used in this experiments. The rats were housed in cages with aluminum floors and received feed and distilled water ad libitum. Animals were divided into three groups, control, low zinc diet and high zinc diet groups. The high zinc diet group was subdivided into 0.5% Zn and 0.7%Zn groups. The supplementary copper or iron was added to the high dietary zinc groups. The animals were sacrificed and the tissues were washed several times with deionized water. The wet digested samples were analyzed by Hitachi Model 207 atomic absorption spectro-photometer for the determination of iron, copper and zinc in the liver and kidney. Hemoglobin level in the blood was measured by cyanmethemoglobin method. The results of this study are as follows: 1) All rats fed high zinc diets and low zinc diets gained less weight than control. Weight gain was not improved by the supplementary copper or iron and both. 2) Hemoglobin concentration was decreased significantly in the rats fed high zinc diets and less in the low zinc diet. Supplementary copper and iron to the higher zinc diet appeared to give some improvement of anemia. 3) The iron contents of the liver and kidneys were significantly decreased in the high zinc groups and the reduction was more significantly in the rats receiving higher zinc diet (0.7%). The supplementary copper caused a further depression of liver iron. On the other hand, the iron, added to the high zinc diet lessoned the severity of the decrease in liver iron and caused kidney iron to be maintained almost at the level found in the rats fed by zinc and supplementary copper diet. 4) High zinc diets did not change copper content of the liver and kidney. Supplementary copper elevated the concentration in the liver and kidney and added iron had no effect on the accumulation of copper in the liver and kidneys. 5) The high zinc diets caused marked increases of zinc content in the liver and kidney. Supplementary iron to the high zinc diet caused increases of zinc contents of liver and kidneys.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.3 s.234
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• pp.462-469
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• 2005

Single phase bainite structure which is obtained by the conventional austempering treatment reduces the ductility of ductile cast iron. Because of the reduction of ductility it is possible to worsen the fatigue properties. Therefore, semi austempered ductile iron which is treated from ${\alpha}+{\gamma}$ is prepared to investigate the static strength and fatigue properties in comparison with fully austempered ductile iron (is treated from ${\gamma}$). In spite of semi austempered ductile iron shows the $86{\%}$ increase of ductility. Also, semi austempered ductile iron shows the higher fatigue limit and lower fatigue crack growth rate as compared with fully austempered ductile iron. By the fractographical analysis, it is revealed that the ferrite obtained by semi austempering process brings about the plastic deformation(ductile striation) of crack tip and gives the prior path of crack propagation. The relatively low crack growth rate in semi austempered specimen is caused by above fractographical reasons.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.1922-1928
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• 1999

Rotary bending fatigue tests were carried out to investigate the influence of artificial defects on fatigue limit in annealed and austempered ductile iron. Obtained main results are as follows : (1) Artificial defect(micro hole type, dia.<0.4 mm) on specimen surface did not bring about a obvious reduction of fatigue limit in austempered ductile iron(ADI) as compared with annealed ductile iron. (2) According to the investigation of $\sqrt{area}_c$ which is the critical defect size to crack initiation at artificial defect, $\sqrt{area}_c$ of ADI is larger than that of annealed ductile iron. This shows that the situation of crack initiation at artificial defect in ADI is more difficult in comparison with annealed ductile iron. (3) One of the reasons for the low rate of crack initiation from artificial defect in ADI is that the resistance of matrix to crack initiation is higher than that of annealed ductile iron. (4) In case that the $\sqrt{area}$ of artificial defect and graphite nodule is the same, the rate of crack initiation from graphite nodule is higher than that from artificial defect. This reason is that the serious ruggedness around graphite nodule is formed by austempering treatment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.127-133
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• 2009

In order to determine organic carbon oxidation by manganese and iron oxides, six core sediments were obtained in slope and basin sediments of Ulleung Basin in East Sea. The basin sediments show high organic carbon contents (>2%) at the water depths deeper than 2,000 m; this is rare for deep-sea sediments, except for those of the Black Sea and Chilean upwelling regions. In the Ullleung Basin, the surface sediments were extremely enriched by Manganese oxides with more than 2%. Maximum contents of Fe oxides were found at the depth of $1{\sim}4cm$ in basin sediments. However, the high level of Mn and Fe oxides was not observed in slope sediment. Surface manganese enrichments (>2%) in Ulleung Basin may be explained by two possible mechanisms: high organic carbon contents and optimum sedimentation rates and sufficient supply of dissolved Manganese from slope to the deep basin. Reduction rates of iron and manganese oxides ranged from 0.10 to $0.24\;mmol\;m^{-2}day^{-1}$ and from 0.30 to $0.57\;mmol\;m^{-2}day^{-1}$, respectively. In Ulleung Basin sediments, $13{\sim}26%$ of organic carbon oxidation may be linked to the reduction of iron and manganese oxides. Reduction rates of metal oxides were comparable to those of Chilean upwelling regions, and lower than those of Danish coastal sediments.

• Journal of the Korean Ceramic Society
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• v.53 no.4
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• pp.444-449
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• 2016

Industrial by-products generated by integrated iron and steel manufacture cause environmental pollution. The by-products contain not only iron element but also harmful substances. Therefore, in view of to waste recycling and environmental preservation, production of sponge iron using the by-product is considered an effective recycling method. In this study, reduction efficiency of pellets from blast furnace dust was measured. Metallization was found to be increased, as $C/Fe_{total}$ ratio and reaction time were increased. The pellets were formed into a globular shape, and calcined for 60 minutes at $1100^{\circ}C$ in an electric furnace. Phase changes were analyzed using an X-ray diffractometer. Microstructures of the pellets were observed by a scanning electron microscope.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.387-392
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• 2001

Kobe Steel, LTD. and Midrex Technologies Inc. jointly developed the FASTMET$\circledR$ process as a steel mill waste recycle technology in which the DRI product meets BF feed material or BOF/EAF feed material requirements. FASTMET(R) process turns value-less wastes into valuable DRI and sellable zinc oxide, and gives the solution for the steel mill wastes recycling from both economical and environmental viewpoints. During the development of the process, Laboratory, Pilot Plant and Demonstration Plant tests were carried out from 1990 to 1998. The first FASTMET(R) commercial plant began operation in April, 2000 and the second commercial plant started in April, 2001 Both commercial plants have proceeded successfully preying that FASTMET$\circledR$ is a suitable process for recycling steel mill waste and for producing DRI as an iron source.