• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.387-394
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• 2008

The Physical property changes of calcined clay by carburization were investigated studied. The carburization mechanism is the penetration of carbon which occurred during incomplete fuel combustion into crevice of clay structure. The experiments for elasticity and freeze-thaw resistance were conducted, and the results can be summarized as follows: Dynamic modulus of elasticity and also freeze-thaw resistance of calcined clay by carburization treatment increased more than 92% after testing 300 cycle, which was more improved than 88% of calcined clay. Therefore, it can decrease the possibility of winter-sowing, which is one the weakness of calcined clay. It is on the basis of the fact that the porosity of calcined clay by carburization treatment is about 12%, which indicates smaller pore spaces comparing with the 14% of porosity of calcined clay and those values were calculated by apparent porosity show and also supported by SEM images. Infrared emissivity of calcined clay by carburization treatment and calcined clay were respectively 0.92 and 0.9l at $80^{\circ}C$. However, those values were 0.91 and 0.88 at $200^{\circ}C$, which means infrared emissivity of calcined clay by carburization treatment shows 3.6% higher than the calcined clay. Moreover, within the wavelength range from 3 to $7\;{\mu}m$, while the calcined clay had low infrared emissivity, the calcined clay by carburization treatment had increased infrared emissivity. It is inferred that it was affected by carbon element that has high infrared absorptivity within this wavelength range.

• Polymer(Korea)
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• v.34 no.3
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• pp.215-219
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• 2010

Nitrile rubber (NBR) composites were prepared using the commercially avaliable rubber compounding process with Cloisite$^{(R)}$ 10A or carbon black as fillers. When Cloisite$^{(R)}$ 10A was used as a filler in the NBR composites, the mechanical properties, oil resistant, and oxygen barrier were better than those for carbon black composites. In cure characteristics of NBR/clay composites, scorch time and curing time were reduced. It was found that alkyl ammonium ion inserted in Cloisite$^{(R)}$ 10A was considered as an accelerator of vulcanization for NBR composites.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.55-61
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• 2012

The ability of clay mineral to remove non-point sources such as SS, COD, T-N. T-P in the urban runoff has been tested to develop the porous filter material. The diameter of 3mm ball type filters were made of clay minerals for the tests. The experiments were carried out to measure the concentration of non-point sources of contaminants with flow rate of effluents. The test results show that clay filter has good response to remove SS, COD comparing to those of activated carbon filter. Also the performance of the clay filter to remove T-N and T-P is almost the same when using the activated carbon filter.

• Elastomers and Composites
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• v.39 no.1
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• pp.51-60
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• 2004

The cure, viscoelastic and mechanical characteristics of organoclay filled NR/BR blends were studied and compared with the properties of carbon black and silica filled NR/BR blends. The nanocomposites with extensive exfoliation state can be fabricated by a solution mixing method. In the composites, the amount of filler content was fixed to 10 phr. Degree of intercalation and exfoliation was characterized by X-ray diffraction (XRD). XRD results indicated exfoliation of the silicate layers into the rubber matrix. While the degree or intercalation and exfoliation is lowered by the conventional mixing method, extensive exfoliation can be obtained by the solution mixing method. It was found that the clay filled NR/BR compound showed better viscoelastic (tan ${\delta}$) and mechanical properties than the carbon black or silica filled NR/BR compounds.

• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.57-62
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• 2018

This study was designed to analyze the chemical composition and antioxidant activity of various vegetable oils (pumpkin seed oil, camellia seed oil, red pepper seed oil and peanut oil) using adsorbents (active carbon, acid clay, kaolin). Their chemical composition was analyzed by GCMS. Their antioxidant activity was evaluated by measuring their DPPH and ABTS radical scavenging activity. After the treatment with the adsorbents, the contents of most of the fatty acids and active ingredients contained in the four kinds of vegetable oils were reduced. After the treatment with the three adsorbents, the linoleic acid and erythrodiol contents of the pumpkin seed oil were reduced. In the case of the camellia seed oil, the fatty acids content was decreased, but there was no loss of vitamin E after the acid clay treatment. The content of the compound capsaicin, which forms part of the spicy component of red pepper seed oil, was reduced by 53.33% after the acid clay treatment. The peanut oil showed the lowest loss of sitosterol compound in the group treated with active carbon. The antioxidant activity was observed to be in the order of pumpkin seed oil (kaolin>acid clay>active carbon), camellia seed oil (acid clay>kaolin>active carbon), red pepper seed oil (kaolin>acid clay>active carbon) and peanut oil (active carbon>acid clay>kaolin).

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.63-65
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• 2008

The increased interest in reducing the environmental effects caused by releasing organic compounds and aqueous waste has motivated the development of polymeric materials in supercritical fluids. Recently, supercritical fluids have been used in material synthesis and processing because of their special properties, such as high diffusivity, low viscosity, and low surface tension. Supercritical carbon dioxide is the most attractive because it is non-toxic, non-flammable, and has moderate critical temperature and critical pressure values. Supercritical carbon dioxide can also swell most polymers. In this study, we prepared polymer/clay nanocomposites using supercritical fluids. Cloisites 10A, 15A, 25A, and 30B used in this study are montmorillonites modified with a quaternary ammonium salt. The nanocomposites of polymer/clay were characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry.

• Economic and Environmental Geology
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• v.32 no.2
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• pp.151-159
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• 1999

This research was carried out to evaluate the possible usage of natural clay materials collected from the Kimpo landfill site and nearby clay mines as a clay liner material. In order to evaluate the possible usage as a clay liner material, specific gravity, pH, loss-on-ignition, organic carbon content and mineralogical composition of clay materials were measured. The Atterberg limit test and the size analysis were performed for the engineering classification and the prediction of hydraulic conductivity of clay materials. Caution exchange capacity and batch tests were also carried out for the assessment of attenuation capacity. Clay specimens of KPNCL, KP-1, KP-2 and SH were recommended as suitable clay linder materials from viewpoint of their basic quality and attenuation capacity.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.143-150
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• 2014

Recently, supercritical fluid process has been widely used in material synthesis and processing due to their remarkable properties such as high diffusivity, low viscosity, and low surface tension. Supercritical carbon dioxide is the most attractive solvent owing to their characteristics including non-toxic, non-flammable, chemically inert, and also it has moderate critical temperature and critical pressure. In addition, supercritical carbon dioxide would dissolve many small organic molecules and most polymers. In this study, we have prepared the poly (ethylene oxide)/clay nanocomposites using supercritical fluid as a carbon dioxide. Commercialized Cloisites-15A and Cloisites-30B used in this study, which are modified with quaternary ammonium salts. The nanocomposites of polymer/clay were characterized by XRD, TGA and DSC. Poly (ethylene oxide)/clay nanocomposites by supercritical fluid show higher thermal stability than nanocomposites prepared by melt process. In addition, supercritical fluid process would be increased dispersibility of the nanoclay in the matrix.

• Journal of Ceramic Processing Research
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• v.19 no.6
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• pp.483-491
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• 2018

Effects of additives on phase development and physico-mechanical properties of mullite-carbon was investigated. Powdered clay, kaolinite and graphite of predetermined compositions were blended with additives using ball mill for 3 hrs at 60 rev/min. Samples were produced by uniaxial compression and sintered between $1400^{\circ}C$ and $1600^{\circ}C$ for one hr. They were characterized for various properties, developed phases and microstructural features. It was observed that the properties and phase developments in the samples were influenced by the additives. 10 wt % SiC served as nucleating point for SiC around $1400^{\circ}C$. 10wt % $TiO_2$ lead to development of 2.5 wt % TiC at $1500^{\circ}C$ which increased to 6.8 wt % at $1600^{\circ}C$. Ifon clay in the sample leads to development of anorthite and microcline in the samples. 10wt % $TiO_2$ is effective as anti-oxidant for graphite up to $1500^{\circ}C$. Base on strength and absorbed energy, sample C (with 10wt % $TiO_2$) sintered at $1500^{\circ}C$ is considered to be optimum.