• Journal of the East Asian Society of Dietary Life
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• v.20 no.3
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• pp.452-457
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• 2010

To obtain basic information on the utilization of Suaeda (S.) asparagoides $M_{IQ}$ as a raw material in food, it's chemical components of were investigated. S. asparagoides $M_{IQ}$ from the Hwaseong-si in Korea was used after drying and grinding with powder. The total dietary fiber, insoluble dietary fiber and soluble dietary fiber contents of S. asparagoides $M_{IQ}$ were found to be 39.41%, 37.63% and 1.78%, respectively. Macromineral components of S. asparagoides $M_{IQ}$ were Na (7.6%), K (2.4%) and Mg (0.6%). High contents of microminerals such as Cu, Mn and Zn were also found. Lysine and methionine which are essential amino acids were detected with the value of 215 mg/100 g and 23.2 mg/100 g, respectively. S. asparagoides $M_{IQ}$ that was harvested in May was higher in crude protein than that harvested in September but the crude fat content of that which was harvested in September was twice as high as that harvested in May.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.56.2-56.2
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• 2012

Clinically-favored materials for bone regeneration are mainly based on bioceramics due to their chemical similarity to the mineral phase of bone. A successful scaffold in bone regeneration should have a 3D interconnected pore structure with the proper biodegradability, biocompatibility, bioactivity, and mechanical property. The pore architecture and mechanical properties mainly dependent on the fabrication process. Bioceramics scaffolds are fabricated by polymer sponge method, freeze drying, and melt molding process in general. However, these typical processes have some shortcomings in both the structure and interconnectivity of pores and in controlling the mechanical stability. To overcome this limitation, the rapid prototyping (RP) technique have newly proposed. Researchers have suggested RP system in fabricating bioceramics scaffolds for bone tissue regeneration using selective laser sintering, powder printing with an organic binder to form green bodies prior to sintering. Meanwhile, sintering process in high temperature leads to bad cost performance, unexpected crystallization, unstable mechanical property, and low bio-functional performance. The development of RP process without high thermal treatment is especially important to enhance biofunctional performance of scaffold. The purpose of this study is development of new process to fabricate ceramic scaffold at room temperature. The structural properties of the scaffolds were analyzed by XRD, FE-SEM and TEM studies. The biological performance of the scaffolds was also evaluated by monitoring the cellular activity.

• Korean Journal of Materials Research
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• v.25 no.7
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• pp.330-335
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• 2015

A low thermal expansion ceramic, cordierite ($2MgO{\cdot}2Al_2O_3{\cdot}5SiO_2$), was synthesized using pyrophyllite. Pyrophyllite usually consists of $SiO_2$ and $Al_2O_3$, which are the main components of cordierite. $MgCO_3$ and $Al(OH)_3$ were added in various amounts to pyrophyllite and fired for synthesis and sintering. ${\alpha}$-cordierite crystallized from $1000^{\circ}C$ with mixing of 20 wt% $MgCO_3$ and 1.7 wt% $Al(OH)_3$, and un-reacted cristobalite was also detected with the cordierite. As the temperature was increased to $1400^{\circ}C$, the cordierite yield was gradually increased. Powder compacts of the synthesized cordierite were sintered between $1250^{\circ}C{\sim}1400^{\circ}C$; the sintered samples showed a low thermal expansion coefficient of $2.1{\times}10^{-6}/^{\circ}C$ and typical sintering behavior. It is anticipated that it will be possible to synthesize cordierite ceramics on a mass production scale using the mineral pyrophyllite.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.425-428
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• 2005

In this study, the experiment was carried out to investigate and analyze the strength properties and flowability of concrete using meta kaolin. The main experimental variables were water/binder ratio 40.0$\%$, water content 170kg/$m^{3}$ and mineral admixtures such as slag powder, silica fume and meta kaolin. According to the test results, the principle conclusions are summarized as follows. 1) The flowing property of concrete that uses meta kaolin appears to be the same to that of the silica fume concrete, but the slump flow that evaluates the compaction ability of concrete shows the most favorable performance. 2) The air content of the concrete that uses meta kaolin can be effectively controlled for the target performance in compliance with the use of AE agent. 3) When it comes to the strength of concrete that uses meta kaolin, the most favorable development of strength occurs when the replacement rate is 10$\%$, in case of the silica fume, and the slag power. In addition, as the replacement rate increases, so becomes the development of concrete strength favorable.

• Journal of the Korean Ceramic Society
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• v.17 no.2
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• pp.61-68
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• 1980

The effect of the addition of various fluoreides on the mullitization of Korean crude kaolin was studied by X-ray powder diffraction and scanning electron microscopic methods. Kaolin without any addition of fluoreides began to be transformed into the mullite at 1, 10$0^{\circ}C$. Mullite peaks were discernible in the X-ray diffraction patterns of the specimens which contained fluorides equivalent to about 2 wt % fluorine, and which were sintered at 1, 05$0^{\circ}C$. The higher the concentration of fluorine in kaolin, the lower was the initiatinig temperature of mullitization. Experiments , for example, showed that mullite could be formed at 95$0^{\circ}C$ from kaolin mixed with 3.4% fluorine. Of the fluoride, addtives, sodiumsiliconfluoride $(Na_2SiF_6)$ was must effective in mullite formation of kaolin. In order of accelerating mullitization, the fluorides except $Na_2SiF_6$ could be placed in following sequence ; (1) sodium (NaF) (2) aluminium$(AlF_3)$ (3)potassium(KF) (4) ammonium$(NH_4F)$ (5) magnesium$(MgF_2)$ (6) calcium$(CaF_2)$. It was considered that the intrinsic characteristics of fluorides, such as size of ionic radiu, charge , bond strength between cation and anion, and electronegativity of cation affected millitization of halloysite, a main constituent mineral of kaolin.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.601-607
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• 2012

The alkali-activation reaction of two types of typical kaolin calcined at various lower temperatures was investigated at room temperature and at elevated temperatures. For the assessment of the reactivity, the temperature increase and the setting time of pastes prepared with calcined kaolin and sodium/potassium hydroxide solution were measured. Unlike raw kaolin, calcined kaolin samples prepared at various temperature showed an alkali-activation reaction according to the different aspects of the changes in the mineral phases. The reactivity with alkaline solutions was exceedingly activated in the samples calcined at $600-650^{\circ}C$, but the reactivity gradually decreased as the temperature increased in a higher temperature range, most likely due to the changes in the crystal structure of the dehydrated kaolin. The activation effect of the calcination treatment was achieved at reaction temperatures that exceeded $60^{\circ}C$ and was enhanced as the temperature increased. The reactivity of the calcined kaolin with an alkaline solution was more enhanced with the solution of a higher concentration and with a solution prepared from sodium hydroxide rather than potassium hydroxide.

• Korean Journal of Materials Research
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• v.29 no.7
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• pp.425-431
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• 2019

Generally, ceramic tiles for building construction are manufactured by dry forming process using granular powders prepared by spray drying process after mixing and grinding of mineral raw materials. In recent years, as the demand for large ceramic tiles with natural texture has increased, the development of granule powders with high packing ratio and excellent flowability has become more important. In this study, ceramic tile granule powders are coated with hydrophobically treated silica nanoparticles. The effects of hydrophobic silica coating on the flowability of granule powders and the strength of the green body are investigated in detail. Silica nanoparticles are hydrophobically treated with GPTMS(3-glycidoxypropyl trimethoxy silane), which is an epoxy-based silane coupling agent. As the coating concentration increases, the angle of repose and the compressibility decrease. The tap density and flowability index increase after silica coating treatment. These results indicate that hydrophobic treatment can improve the flowability of the granular powder, and prevent cracking of green body at high pressure molding.

• Journal of Ceramic Processing Research
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• v.20 no.spc1
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• pp.109-112
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• 2019

γ-dicalcium silicate(γ-C2S) is known as a polymorphism of belite. Due to its high CO2 fixed capacity and the low CO2 emission production process, γ-C2S has attracted more and more attention of researchers. For the further development of application of γ-C2S in building construction industry. In this study, we aim to investigate the method for synthesizing high purity of γ-C2S. The influence of different raw materials and calcination temperatures on the purity of γ-C2S was also evaluated. Several Ca bearing materials were selected as the calcium source, the materials which' s main component is SiO2 were used as the silicon source. Raw materials were mixed and were calcined under different temperatures. The results reveal that the highest purity could be obtained using Ca(OH)2 and SiO2 powder as raw materials. And for the practical application, a relatively economic synthesis method using natural mineral materials- limestone and silica sand as raw materials was developed, by this method, the purity of the synthetic γ-C2S was 77.6%.

• Journal of Information Processing Systems
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• v.18 no.4
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• pp.457-469
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• 2022

Hydraulic concrete buildings in the northwest of China are often subject to the combined effects of low-temperature frost damage, during drying and wetting cycles, and salt erosion, so the study of concrete deterioration prediction is of major importance. The prediction model of the relative dynamic elastic modulus (RDEM) of four different kinds of modified concrete under the special environment in the northwest of China was established using Grey residual Markov theory. Based on the available test data, modified values of the dynamic elastic modulus were obtained based on the Grey GM(1,1) model and the residual GM(1,1) model, combined with the Markov sign correction, and the dynamic elastic modulus of concrete was predicted. The computational analysis showed that the maximum relative error of the corrected dynamic elastic modulus was significantly reduced, from 1.599% to 0.270% for the BS2 group. The analysis error showed that the model was more adjusted to the concrete mixed with fly ash and mineral powder, and its calculation error was significantly lower than that of the rest of the groups. The analysis of the data for each group proved that the model could predict the loss of dynamic elastic modulus of the deterioration of the concrete effectively, as well as the number of cycles when the concrete reached the damaged state.

• Food Science and Preservation
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• v.20 no.6
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• pp.863-870
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• 2013

This study was conducted to investigate the quality characteristics of kimchi with Allium hookeri powder (AHP) added during eight weeks fermentation at $4^{\circ}C$. AHP was added to salted cabbage at concentrations of 0, 0.1, 1, and 5% (w/w). The quality characteristics of the AHR-added kimchi were determined by measuring pH, acidity, salinity, reducing sugar, microbial amounts, and sensory properties. The vitamin $B_1$ and vitamin C contents of the Allium hookeri root were 0.04 mg/100 g and 5.76 mg/100 g, respectively. As for the mineral contents, the K content was highest, followed by the Ca, Mg, and Fe contents. The pH was higher in the kimchi with 0.1%, 1%, and 5% AHP than in the kimchi without AHP during the eight-week fermentation. The salinity ranged from 2.02% to 2.37% over the eight weeks. The microbial cells and lactobacilli increased rapidly throughout the fermentation in the exponential phase and hardly increased in the stationary phase. In the sensory evaluations, the overall acceptance, taste, and texture of the kimchi with 1% AHP added were highest. In conclusion, the kimchi with 0.1%, 1%, and 5% AHP generally showed better quality than the kimchi without AHP. Especially, the kimchi with 1% AHP had the best scores in quality and overall acceptance during the fermentation.