The Fabrication of Artificial Fine Aggregates Using Stone Sludge and Spent Bleaching Clay

Kim, Kangduk The Korean Ceramic Society 2014 한국세라믹학회지 Vol.51 No.5

Artificial fine aggregates (denoted AFA) were fabricated using spent bleaching clay (denoted SBC) generated from processed vegetable oil and stone sludge (denoted SS) produced from crushed aggregate manufacturing materials for use as functional construction materials. Each raw material was crushed to particle size finer than $150{\mu}m$, and fine spherical pellets of approximately 1 ~ 4 mm in diameter were prepared by a pelletizing process. The physical properties of the AFA were measured with different types of sintering equipment. A new type of vertical furnace that sinters fine aggregates in a fluidized bed at high temperatures was designed and tested. AFA sintered in a rotary kiln at $1125^{\circ}C$ showed a bulk density of $1.5g/cm^3$ and a water absorption of 16%. AFA sintered in the vertical furnace at $1125^{\circ}C$ showed a bulk density of $1.9g/cm^3$ and water absorption of 8.5%. The bulk density of the AFA sintered in the vertical furnace showed a bulk density 27% higher and water absorption 47% lower than those of AFA sintered in the rotary kiln.

Effects of ZnO and Al2O3 on optical properties of sanitary ware glazes without ZrSiO4

Yeonju Kim,Kangduk Kim,Kyu-sung Han 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.6

In this study, to replace zirconia-based white glaze, 3 wt% TiO2 was added to CaO-Al2O3-SiO2-ZnO with a translucent glaze, and ZnO and Al2O3 were added to suppress the yellowing of TiO2. According to the type and amount of additives, the crystal phases (X-ray diffraction, XRD) and microstructures (scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS)) of the glazes were analyzed, and the whiteness, gloss, reflectance, and absorption coefficient were measured. XRD and SEM analyses revealed the presence of plate-like (SiO2) and needle-like (Al1.488Ca0.491Na0.499Si2.506O8) crystal phases that affected the whiteness of the glaze. The gloss of the specimen was significantly reduced (to <40) with the addition of Al2O3. Color analysis results revealed a yellow index (b*) ranging from 2.8% to 4.9% and whiteness ranging from 89% to 93% for all the specimens, which were similar to the values for the zirconia-based white glaze. Reflectance analysis in the visible range (300–800 nm) using Ultraviolet–visible–near-infrared spectrophotometer (UV-ViS-NIR) indicated a decrease in reflectance in the wavelength range of 400-500 nm and an increase in reflectance in the wavelength range of 500-700 nm.

Effect of Rutile/Anatase TiO2 on surface properties of ZnO-Al2O3-CaO-SiO2 glass system

Dongchan Kim,Seunggu Kang,Kangduk Kim 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.5

In this study, we investigated the effects of dimorphous nucleating agentsrutile TiO2 and anatase TiO2, on the crystallizationand surface properties of ZnO-Al2O3-CaO-SiO2-based glass. Glass specimens were prepared by substituting rutile TiO2 andanatase TiO2 at 1, 3, and 5 wt.% and subsequently heat treating at 1050 °C for 90 min to induce crystallization. Thecrystallization characteristics and surface properties of the crystallized glass were analyzed using X-ray diffraction (XRD),scanning electron microscopy (SEM), gloss, Fourier-transform infrared (FTIR) spectroscopy, hardness, and colorimetricanalyses. The XRD and SEM analyses revealed the presence of a titanite crystalline phase in the glass matrix. However, theaddition of anatase TiO2 as a nucleating agent resulted in a significant decrease in glossiness. FTIR deconvolution in the rangeof 800-1300 cm−1 showed an increase in the degree of [SiO4] tetrahedral polymerization with higher levels of crystallization. micro-Vickers hardness of the glass specimens increased from the original value of 6.32 GPa to a maximum of 7.05 GPa,indicating enhanced hardness due to crystallization. Colorimetric analysis indicated that the inclusion of rutile TiO2 as anucleating agent increased the Yellow Index of anatase TiO2.

Slitrks control excitatory and inhibitory synapse formation with LAR receptor protein tyrosine phosphatases

Yim, Yeong Shin,Kwon, Younghee,Nam, Jungyong,Yoon, Hong In,Lee, Kangduk,Kim, Dong Goo,Kim, Eunjoon,Kim, Chul Hoon,Ko, Jaewon National Academy of Sciences 2013 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.110 No.10

<P>The balance between excitatory and inhibitory synaptic inputs, which is governed by multiple synapse organizers, controls neural circuit functions and behaviors. Slit- and Trk-like proteins (Slitrks) are a family of synapse organizers, whose emerging synaptic roles are incompletely understood. Here, we report that Slitrks are enriched in postsynaptic densities in rat brains. Overexpression of Slitrks promoted synapse formation, whereas RNAi-mediated knockdown of Slitrks decreased synapse density. Intriguingly, Slitrks were required for both excitatory and inhibitory synapse formation in an isoform-dependent manner. Moreover, Slitrks required distinct members of the leukocyte antigen-related receptor protein tyrosine phosphatase (LAR-RPTP) family to trigger synapse formation. Protein tyrosine phosphatase σ (PTPσ), in particular, was specifically required for excitatory synaptic differentiation by Slitrks, whereas PTPδ was necessary for inhibitory synapse differentiation. Taken together, these data suggest that combinatorial interactions of Slitrks with LAR-RPTP family members maintain synapse formation to coordinate excitatory–inhibitory balance.</P>

자력선별법을 이용한 화력 발전소 매립회의 지오폴리머 원료화 연구

김강덕,Kim, Kangduk 한국결정성장학회 2017 한국결정성장학회지 Vol.27 No.5

화력발전소에서 발생되는 매립회의 지오폴리머 원료화를 위하여 자력선별 공정을 이용하여 자성체와 비자성체로 분리하였으며, 매립회의 입도 및 자석의 세기에 따른 미연탄소의 선별 특성을 관찰하였다. 3000 G 자석을 이용한 세립(0.15~0.84 mm)과 조립(0.84~2.4 mm) 매립회의 자력선별 결과, 매립회는 입도에 상관없이 비자성체의 무게분율과 강열감량이 자성체보다 높게 나타났으며, 세립 매립회의 경우 자석의 세기를 3000 G에서 10000 G로 증가시키면, 약한 자성을 띠는 물질들도 자성체로 분리됨에 따라 자성체의 무게 분율이 급격히 증가되면서 낮은 강열감량에도 불구하고 전체 강열감량의 32.6 wt%의 66.9 %(22.8 wt%)를 차지하였다. 자력 선별된 조립 매립회로 제조된 지오폴리머의 재령일별 압축강도 측정결과, 미연탄이 적게 포함된 자성체로 제조된 지오폴리머의 압축강도가 20 MPa를 나타내었다. Using a magnetic separation process, pond ash generated in thermoelectric power plants was separated into magnetic materials and nonmagnetic materials in order to make it into a raw material of geopolymers and unburned carbon; screening characteristics according to the particle sizes and magnet strength levels of the pond ash were observed. Based on the results of magnetic separation into fine particle (0.15~0.84 mm) and rough particle (0.84~2.4 mm) pond ash using 3000 G magnets, the weight fraction and ignition loss of nonmagnetic materials were found to be higher than those of magnetic materials, regardless of the particle size. In the case of fine particle pond ash, when the magnet strength was increased from 3000 G to 10000 G, even those materials that were weakly magnetic were separated into magnetic materials, leading to drastic increases in the weight fraction of magnetic materials, such that the ignition loss accounted for 66.9 % (22.8 wt%) of the entire ignition loss of 32.6 wt%, despite of the low ignition loss. Based on the results of measurement of the compressive strength levels of geopolymers made of magnetic-separated rough particle pond ash, the compressive strength of geopolymers made of magnetic materials containing small amounts of unburned carbon was found to be 20 MPa.

석탄바닥재-적점토계 인공골재의 특성평가

김강덕,강승구,Kim, Kangduk,Kang, Seunggu 한국결정성장학회 2012 韓國結晶成長學會誌 Vol.22 No.6

화력발전소에서 발생되는 석탄 바닥재(이하 바닥재로 칭함)를 재활용하기 위하여 이를 적점토와 혼합, 소성하여 인공골재를 제조함에 있어, 바닥재의 입도와 배합비를 실험변수로 하여 인공골재의 특성을 제어하였다. 채취된 바닥재는 2 mm 이상의 입자들이 38 wt% 존재하는 거친 입도를 나타내었으며, 미연탄 덩어리들과 다공성 슬래그들이 혼재하였으나, 이를 체가름 및 분쇄공정을 통하여 세립(100 ${\mu}m$ 이하) 및 조립(2 mm 이하) 입도를 갖는 2가지 바닥재로 분리하였다. $1100{\sim}1200^{\circ}C$의 조건에서 직화 소성된 인공골재의 물성 측정 결과, 세립 바닥재로 제조된 인공골재는 조립 바닥재로 제조된 경우보다 높은 부피비중과 낮은 흡수율을 나타내었다. 또한 조립 바닥재로 제조된 인공 골재는 내부에 다공성 슬래그와 미연탄 덩어리로 인해 불균일하고 치밀하지 못한 구조를 나타낸 반면, 세립 바닥재로 제조된 인공골재는 상대적으로 치밀하고 균일하였다. 본 연구를 통해 바닥재의 입도 및 조성변화를 통해 인공골재의 비중 및 흡수율을 각각 1.2~1.7 및 13~21 % 범위로 제어할 수 있음을 확인하였고, 따라서 바닥재 인공골재는 향후 건축/토목 등의 재료로 폭넓게 활용될 것으로 기대된다. In order to recycle the coal bottom ashes (denoted as BA) produced from a thermal power plant, the artificial aggregates (denoted as AAs) containing BA and red clay were manufactured, and the physical properties of AAs were studied as a function of particle size of BA and batch compositions. As-received BA had 38 wt% coarse particles of above 2 mm and many unburned carbon mass and porous slag particles were co-existed. So the two particle sizes of BA, the fine (< 100 ${\mu}m$) and coarse (< 2 mm), were prepared by milling and screening process. The AAs containing fine BA sintered at $1100{\sim}1200^{\circ}C$ had the higher bulk density and lower water absorption compared to the specimen made of coarse BA. The inside core of AAs manufactured by using coarse BA showed nonuniform and porous microstructure, while the AAs made of fine BA had a uniform and dense microstructure. In this research, the AAs containing BA and red clay with various bulk density (1.2~1.7) and water absorption (13~21 %) could be manufactured by controlling the particle size of BA and batch compositions, so the AAs of various physical properties could be applied to the wide fields such as construction/building materials in near future.

Effect of TiO2 on the crystallization behaviors and microstructure of glazes based on MgO-Al2O3-SiO2 system

Yoorim Rho,Kangduk Kim,Jin-Ho Kim 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.S1

A MgO-Al2O3-SiO2 system was used in order to prepare glass-ceramic glazes with high-hardness applicable to ceramic tiles. The glass-ceramic glazes were prepared by adding the fluxes CaO and B2O3 and the nucleating agent TiO2 to the glaze. The crystallization behavior of the glaze was calculated by a non-isothermal thermal analysis via a Differential Thermal Analysis (DTA), and the glaze was heat treated at the crystallization temperature (Tp2). The activation energy (E) and the Avrami constant (n) of the glaze with 8wt% TiO2 substitution were 177.07 kJ/mol and 2.65, respectively. X-ray diffraction analysis (XRD) showed that the cordierite and anorthite crystal phases were formed and the karrooite crystal phases grew with increasing TiO2 substitution. The degree of crystallinity increased as the amount of TiO2 increased and the degree of crystallinity was 76.5% in the glaze with 8 wt% TiO2 substitution. In the Scanning Electron Microscope (SEM) analysis, the cordierite and anorthite crystal phases were the largest in the glaze with 8wt% TiO2 substitution and rapidly decreased in the glaze with 12 wt% TiO2 substitution. As a result, Vickers hardness of the glaze showed a high value of 7.10 GPa at the glaze with 8wt% TiO2 substitution after heat treatment at 1,010 oC.

석탄 저회로 제조한 인공토양의 기능성 건설재 적용 가능성

김강덕,이영생,Kim, Kangduk,Lee, Yeongsaeng 한국세라믹학회 2014 한국세라믹학회지 Vol.51 No.4

To recycle coal bottom ash(denoted here as CBA) generated from thermal power plants as a functional construction material, artificial soil(denoted as AS) containing CBA with dredged soil(denoted as DS) at a ratio(wt%) of 70 : 30 was manufactured by means of material engineering with sintering in a rotary kiln at $1125^{\circ}C$ using a green body formed via extrusion processing. The properties of the soil mechanics of the AS and the as-received CBA were analyzed and compared. Compaction testing results determined an optimum moisture content of the AS and CBA at 18%. During these tests, the maximum dry unit weights of the materials were similar, at 1.57 and 1.58 $t/m^3$, respectively. The compressive strength levels of the AS and CBA concrete specimens were 5.1 and 5.4 $t/m^3$, respectively, both of which increased after materials engineering processing. In a consolidation test, the compression index of the AS and CBA was found to be $0.114{\pm}0.001$ in both cases. The values were similar regardless of the materials engineering processes, but during the consolidation of AS, its coefficient was higher than that of the CBA materials.

인공경량골재 내부에 발생하는 방사형 균열의 억제 방법에 관한 연구

강지민,김강덕,강승구,Kang, Jimin,Kim, Kangduk,Kang, Seunggu 한국결정성장학회 2015 韓國結晶成長學會誌 Vol.25 No.5

본 연구에서는 잔사회와 준설토로 제조된 구형의 인공경량골재 내부에 생성되는 방사형 균열의 원인 및 그 억제 방법에 대하여 연구하였다. 인공경량골재는 잔사회와 준설토를 각각 7 : 3의 무게 비로 혼합하고 직경이 5~20 mm인 구 형태로 성형한 후 $1200^{\circ}C$에서 10분간 직화소성법으로 제조하였다. 골재 내부의 균열은 골재 지름이 작을수록 발생이 억제되었다. 또한 $SiO_2$ 분말을 첨가한 경우, 분말의 크기가 클수록 또는 첨가량이 증가할수록 방사형 균열 발생이 억제되었다. 균열이 억제된 인공경량골재의 비중은 1.3~1.6이고, 흡수율은 5~20 %의 범위를 나타내었다. 따라서 본 논문에서 제조된 인공경량골재는 건설 및 환경소재 등 여러 분야에 적용 가능할 것으로 보이며, 더불어 잔사회 및 준설토의 재활용율을 높이는데 크게 기여할 것으로 기대된다. In this study, prevention methods of radial cracks generated inside of artificial lightweight aggregate made of reject ash and dredged soil were investigated. The reject ash and dredged soil had mixed with weight ratio of 7 : 3 and formed to spheric shape of 5~20 mm diameter, then, the aggregates were manufactured using flash sintering method at $1200^{\circ}C$ for 10 min. The formation of radial cracks in the aggregates were suppressed as the size of specimen decreased. Also, the addition of silica to aggregates had prevented generation of the radial cracks. As the size and the amount of silica powder added increased, the development of radial cracks was constrained. Therefore the artificial lightweight aggregate manufactured in this study expected to be applicable to many fields such as construction and environmental usages. Also it is expected to contribute greatly to increase the recycling rate of reject ash and dredged soil.

Polymorphism of Natural Resistance-Associated Macrophage Protein 1 Gene in Hy-Line Chicks infected Salmonella gallinarum

Baatartsogt. O,Erdenesuvd. J,Suh S.W,Kim Y.K,Kim Y.Y,Anh K.C,Lim H.K,Choi Kangduk 한국가금학회 2009 한국가금학회 정기총회 및 학술발표회 Vol.26 No.-

Salmonella gallinarum (S. gallinarum) is the causative agent of fowl typhoid, a severe systemic disease of chickens that results in high mortality amongst infected flocks. Due to its virulence, the immune response to S.gallinarum is poorly characterized. The natural resistance-associated macrophage protein 1 (NRAMP1) affects host innate immunity to intracellular bacteria because of its ability to transport divalent cations in late endosome/lysosomes. The objectives of this study were to identify single nucleotide polymorphisms of the NRAMP1 gene in Hy-Line chicks by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). A PCR-RFLP method was developed to identify a SacI polymorphism for Ser³??. To investigate associations between an NRAMP1 SNP and resistance against S.gallinarum, two NRAMP1 alleles of a T and C were analyzed to 3 genotypes, TT (802 bp), TC (802, 723 bp and 79 bp), and CC (723 and 79 bp). We evaluated the effect of 3 genotypes, such as TT(66 %), CC (36.9 %) and TC (41.9 %) alleles on mortality after S. gallinarum challenge.