• Journal of the Korean Ceramic Society
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• v.22 no.1
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• pp.5-10
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• 1985

The effect of calcium lignosulfonate (CLS) on the early hydration characteristics for clinker minerals was investigated. In the presence of CLS and unsufficient gypsum The hydration of $C_3$A lowered CLS adsorption to form ettrin-gite and the residual CLS in the liquid phase accelerated the solubility of C4AF hydration. As the result unreacted $Fe^{3+}$ in the liquid phase would be precipitated gelatinously on $C_3$ hydrates and the hydration of $C_3$ could be retarded. But by addition of optimum gypsum into the cement with CLS the presence of $Fe^{3+}$ in the liquid phase were lowered and $C_3$ hydration would be normallized.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.27-28
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• 2020

In this paper, we investigated the performance of synthetic graphene oxide-functionalized carbon nanotubes (GF) to promote cement hydration and increase the mechanical properties of cement paste. The enhancement effect of GF on the various properties of cement paste was evaluated via the mechanical strength, X-ray diffraction, and heat of hydration of cement paste. The results clearly showed that GF incorporation into cement paste promotes the early hydration of cement paste, generates more hydration products, which results in the mechanical improvement of cement paste. The compressive and splitting tensile strength were increased by 32.17% and 17.31%, respectively, compared to ordinary Portland cement at 28 days of hydration.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.660-665
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• 2003

Effect of freezing on the hydration rate and growth characteristics of bean sprout of two domestic cultivars of soybean, Eunha beans and Taegwang beans, was investigated. Freezing of the soybeans at $-80^{\circ}C$ affected characteristics of the hydration and growth of soybean sprout of the beans. Hydration rate of the frozen beans depended on the hydration temperature. It decreased up to 50% at lower than $60^{\circ}C$ of hydration temperature, but it did not decrease at higher than $60^{\circ}C$. Activation energies of frozen Eunha and Taegwang beans were 39.79 and 39.25 kJ/mol, respectively. Kinetic compensation effect between activation energy values and the pre-exponential factor for the hydration of soybeans with or without freezing was observed. Germination rate and thickness of the bean sprout increased by freezing, however, yield and weight were not affected by freezing.

• Journal of Veterinary Clinics
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• v.18 no.3
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• pp.206-210
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• 2001

Various commercial shampoos were frequently prescribed for dermatologic therapy in small animal practice. Skim hydration affected by the shampoos, however, was not evaluated routinely. In order to evaluate the skin hydration for the exact prescription of shampoos method to measure skin hydration of shampoos are needed. This study was undertaken to evaluate the skin hydration effect of shampoo on canine skin using Corneometer. Five healthy dogs were applied with 7 commercial shampoos: Humilac, Sebocalm, Sebolytics, Etiderm, Benzoyl peroxide, HyLyt and Zn-7 Derm. Skin hydrations were evaluated by measurement of electrical capacitance by Corneometer. A statistically significant increase in skim hydration was found 17(p<0.05) and 77 minutes(p<0.01) after application of Humilac indicating a humidifying effect of this product. A statistically significant decrease in skin hydration was found for the Benzoyl peroxide after 77 minutes(p<0.05). No statistically significant differences between the other shampoos were found. None of the products tested had any negative effect on the skin barrier function. The Corneometer was found useful for detecting skin hydration to shampoos and considered as a simple and useful tool for prescription of various shampoos routine practice.

• Journal of the Korean Ceramic Society
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• v.21 no.2
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• pp.143-148
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• 1984

In this study we mainly dealt with the effects of organic retarder(calcium lignosulfate) on the early hydration process of clinker minerals. From a consideration of the hydration process of tricalcium silicate $(C_3S)$ tricalcium silicate $(C_3S)$-tricalcium aluminate $(C_3A)$ tricalcium silicate $(C_3S)$-tetracalcium aluminof-errite $(C_4AF)$ systems with calcium lignosulfate the following results were obtained. 1. when 0.25wt% of CLS was added to $C_3S$ the hydration process was progressed normally but adding of 0.5wt% its hydration was greatly retarded. 2. The hydration of $C_3S$-$C_3A$ system was progressed normally up to 0.5wt% but by adding gypsum its hydration was retarded slightly. 3. The hydration of $C_3S$-$C_4AF$ system was greatly retarded even with 0.25wt% of CLS but by adding gypsum its hydration process was recovered normally.

• Journal of the Korean Ceramic Society
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• v.21 no.4
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• pp.355-360
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• 1984

The effect of 2% of $P_2O_5$ substituted in gypsum(5 mol% as $HPO_3$) on the early hydration characteristics of $C_3A$ were investigated and then gypsum only and gypsum mixed with $Ca(H_2PO_4)_2$.$H_2O$(2% as $P_2O_5$) were studied separately for comparison. The early hydration reaction of $C_3A$ with each gypsum were examined by measuring the rate of heat libera-tion of hydration with calorimeter and by analysing the hydration products with X-ray diffractometer and differential thermal analyser. It was shown that phosphogypsum substituted with $P_2O_6$ in the crystal lattice accelerated exceedingly the formation of the ettrignite and following hydrated products. However the other gypsum especially gypsum without any phosphate delayed the formation of various hydration products, It was consequently suggested that when phosphogypsum are used as the retarder of cement setting its reta-rding effect for setting of cement is not ascribed to the retardation of ettringite formation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.151-152
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• 2023

This study investigates the effect of nano-silica and nano-calcite on the hydration properties and mechanical performance of limestone calcined clay cement (LC³) paste. The pastes were synthesized by replacing limestone with nano-silica and nano-calcite in order to enhance the mechanical properties in both early and late stages of hydration. The nano-calcite enhanced the strength of LC³ pastes at 1 day of hydration, however, the strength decreased compared to the ordinary LC³ pastes afterwards due to excessive amount of carboaluminate produced in the pastes. On the other hand, nano-silica improved the mechanical properties of LC³ pastes at all ages of hydration. This is mainly due to the nucleation effect and pozzolanic reaction of nano-silica, affecting the early age and late ages of hydration, respectively. The nucleation effect of both nanomaterials were confirmed by the analysis of hydration heat, supporting the enhanced early age strength of nanomaterial incorporated LC³ pastes. Furthermore, the dense matrix was shown in the pore size distribution, and the increased C-S-H due to the pozzolanic reaction evidence the improved compressive and splitting tensile strength of nano-silica incorporated LC³ pastes.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.140-143
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• 2004

Heat of hydration of concrete under different curing temperatures can be characterized with knowledge of the thermal activity, the heat rate at the reference temperature, and the total heat of hydration of the mixture. The so-called multi-component hydration model incorporates the effect of following variables: cement chemical composition, cement fineness, secondary cementitious powders, mixture proportions, and concrete properties. However, the model does not consider the use of silica fume as a secondary cementitious powder. Therefore, the model that quantifies the heat of hydration due to the use of silica fume is needed. In this thesis, the effects of silica fume on heat of hydration are evaluated and the influence on the heat of hydration are also quantified to be included in the model, so that the analysis using modified multi-component hydration model for silica fume concrete provides more accurate results than normal concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1041-1044
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• 2008

The addition of chemical inert filler in blended cement, such as limestone or chemical inert silica fume, will produce a physical effect on cement hydration. Due to the high surface area of inert filler in the mixtures, it provides sites for the nucleation and growth of hydration products, thus improving the hydration rate of cement compounds and consequently increasing the strength at early age. This paper proposes a model of hydration of Portland cement blended with chemical inert filler. This model considers the influence of water to cement ratio, cement particle size, cement composition and addition of chemical inert filler on hydration. The heat evolution, degree of hydration and porosity are obtained as accompanied results in hydration process. The prediction results agree well with experiment results.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.53-59
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• 2018

When manufacturing self-healing concrete using bacteria, nutrients are added to increase the activity of the bacteria. Although many researches have focused on the effects of nutrients containing bacterial healing agent on concrete, few have studied the effects of sole nutrient on self-healing of cement composites. Bacterial nutrients, like commercial chemical admixtures, affect hydration characteristics such as flow, setting, hydration heat, mechanical strength of cement composites and also affect the self healing of cement composites by hydration of unhydrated particles. In this study, effect of the four nutrient commonly used in the existing literature on the hydration characteristics of cement composites by its addition was investigated. Flow, setting time, hydration heat, compressive strength have studied for each nutrients added by 1.5% and 3% of cement weight. Experimental results shows that urea and calcium-nitrate can be used up to 3% without significant detrimental effect on cement composites. Addition of calcium-lactate up to 1.5% show better compressive strength than control, but addition of 3% show almost non-hydration. Yeast extract shows detrimental effects on the composites regardless of the amount added.