• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.680-689
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• 1995

Rice based infant foods of carrot, of beef, and of egg for 4-6 month old infants were prepared using freeze drying (FD) process. The optimum moisture content prior to FD and the plate temperature in the drier were determined with the use of response surface methodology. For all the infant foods under this study, FD time was longer as the initial moisture content was higher and the plate temperature was lower. Brittleness of the dried infant foods increased as the moisture content decreased and the plate temperature increased. Among the sensory attributes, hydration rate, uniformity, and smoothness were greater with increased moisture content and with decreased plate temperature. Ease to spoon increased as moisture content increased and mouthcoating increased as both the moisture content and the plate temperature increased. Optimum moisture content and plate temperature for the FD of carrot, beef and egg foods were 88.5% and $34^{\circ}C$, 88.5% and $28^{\circ}C$, and 87.3% and $39^{\circ}C$, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.132-133
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• 2018

The In this study, the change of composition of the hydrates according to the recovery age of concrete in the case of fire damage was confirmed through microscopic analysis. In 28 days of age, the production of ettringite was higher than that of day 1, and the calcium hydroxide was increased in the 91 day. It has been recovered through the generation of major hydrates which affect the strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.144-145
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• 2021

Calcium silicate hydrate(C-S-H) is the principal binding phase that controls the strength and thermal stability of concrete. However, the effects of high temperature on the lattice structure and interatomic structure of C-S-H remains poorly understood due to its nanocrystallinity. This study aims to elucidate the change in interatomic distance of synthetic C-S-H with different Ca/Si molar ratios after exposure to high temperature via high energy X-ray scattering experiment which is a powerful analytical tool for amorphous materials.

• Journal of the Korean Ceramic Society
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• v.11 no.4
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• pp.19-24
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• 1974

The study was investigated to confirm the morphology of crystal from xonotlite to wollastonite at elevated temperature by electron microscopy. Mixtures of slaked lime and powdered quartz with plenty water were oscillated continuously in an autoclave under the pressure of 25kg/$\textrm{cm}^2$ for 8 hours to obtain well crystallized xonotlite. This milky slurry consisting of xonotlite was gained and dried in oven at 11$0^{\circ}C$. Examination of the electron micrograhs showed the xonotlite to be developed thin lath-like crystals and to be formed aggregate as chestnut bur. Details of the morphology suggest that the heat-treated xonotlite up to 100$0^{\circ}C$ splited and deformed slightly in agreement with the topotaxial transformation theory of xonotlite to wollastonite. The molded material endured in good shape under 120$0^{\circ}C$ except a little shrinkage.

• Journal of the Korean Ceramic Society
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• v.11 no.4
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• pp.25-30
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• 1974

The mixture of quartz powder and slaked lime with plenty water was oscillated in an autoclave and treated hydrothermally under the pressure of 10 kg/$\textrm{cm}^2$ for 8 hours. The main mineral synthesized was confirmed 11$\AA$ tobermorite by the method of X-ray diffraction and selected area electron diffraction. Tobermorite was heat-treated at 40$0^{\circ}C$, 80$0^{\circ}C$ and 100$0^{\circ}C$ for investigation of transformation of morphology and structure. Electron micrographs showed the thin platy structure of synthetic tobermorite with a little of crumpled foil or fibrous semi-crystalline calcium silicate hydrates. No difference in structure was appeared under the temperature of 80$0^{\circ}C$ but tobermorite converted gradually into wollastonite at 800$^{\circ}$~85$0^{\circ}C$. On heating, moulded material from tobermorite hardly shrinks under 80$0^{\circ}C$.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.267-268
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• 2009

s manufacturing the Precast Concrete simulation structure, we generally investigated the temperature characteristics of the concrete according to diversity of the cement and heat curing condition respectively.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.799-804
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• 2002

Optimum conditions of freeze-dried carrots were determined using response surface methodology. Physicochemical and sensory properties of freeze-dried carrot prepared at different plate temperatures and chamber pressures were evaluated. Drying time increased with decreasing plate temperature and chamber pressure. Rehydration ratio decreased inversely with chamber pressure at low plate temperature, but increased proportionally with chamber pressure at high temperature. Density, color, and sensory off-flavor were not affected by the plate temperature and chamber pressure. Sensory color, tenderness, and carrot flavor increased with decreasing plate temperature, but were not affected by chamber pressure. Based on the drying time, rehydration ratio, and sensory attributes, optimum plate temperature and chamber pressure for the preparation of freeze-dried carrot were determined as $43^{\circ}C$ and 700 micronHg, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.4
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• pp.174-178
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• 2008

Nano-crystalline slaked lime was synthesized using design of experiment. In order to synthesize slaked lime, calcium chloride $(CaCl_2)$ and urea were used as starting materials. Calcium chloride solution and urea solution were mixed and heated in vessel that calcium carbonate was precipitated during heating. Precipitates were filtered, washed several times using D.I.water and ethanol and finally dried in oven. Slaked lime $(Ca(OH)_2)$ has been fabricated by the hydration of calcined $CaCO_3$. Design of experiment (Taguchi method) was used to optimize parameter, to minimize noise factors of experiment and to statistically analyze the results. Slaked lime having about 50 nm in optimized crystallite size could be obtained by calcination of $CaCO_3$ at $1000^{\circ}C$ for 0.5 h and hydration with D.I water containing ethanol and oxalic acid.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.481-485
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• 1998

Hydrated aluminum sulfate, an inorganic polymer, was synthesized from kaolin in $H_2SO_4$ solution using microwave energy. The maximum rates of alumina extracted from calcined kaolin were 72.8% in a conventional process ($80^{\circ}C$, 1M, and 180min) and 99.9% in a microwave process ($90^{\circ}C$, 1M, and 60 min). Compared with the conventional one, the hydrated aluminum sulfate synthesized under the microwave process had layer structure consisting of plate-shaped large grains. After synthesis and then calcination at $1100^{\circ}C$, both products on conventional and microwave processes were ${\gamma}-Al_2O_3$ with agglomerated powders of spherical shape. The specific area of the products in conventional and microwave processes were 113.5 and $106.6m^2/g$, and their average grain sizes were 46.5 an $26.3{\mu}m$, respectively.

• Journal of the Korea Institute of Building Construction
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• v.16 no.1
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• pp.1-7
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• 2016

In this research, it used cement powder and reduction slag, which generates high hydration heat in hydration reaction without heat cure below $-5^{\circ}C$ degree. Purpose of final research is preventing freezing and thawing by making the compressive strength 5MPa in 3days below zero temperature due to own heat of concrete. and it is the result of physical characteristic and thermal property evaluation of reduction slag. Because reduction slag generates high hydration heat, compressive strength development is excellent. By generating highly hydration heat by $C_{12}A_7$ and $C_3A$ in reduction slag, compressive strength is developed in low temperature. In case of displacing only reduction slag without $SO_3$, it is indicated that quick-setting occurs by shortage of $SO_3$. For preventing quick-setting, gypsum is used essentially. According to this research result, in case of using reduction slag and gypsum as a ternary system, compressive strength developed 5MPa in 3 days below zero temperature. It is identified to prevent early frost damage of concrete below zero temperature.