• Journal of the Korea Institute of Building Construction
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• v.17 no.3
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• pp.269-277
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• 2017

In this work, as a preliminary experimental works, which focuses on utilizing separated pastes from activated (or radioactive) concrete as solidifying agents for radioactive waste immobilization, were performed. It was found that density of hydrated cement paste, which was lower than that of ordinary portland cement, increased as temperature for heat treatment increased. Highest compressive strength was observed with the specimens that was heat treated at $600^{\circ}C$. However, heat treatment over $700^{\circ}C$ showed higher CaO content that caused higher heat of hydration after in contact with water, lows of workability, and lower strength. Based on experimental results, it is suggested that $600^{\circ}C$ heat treatment is more appropriate for waste cement paste to be used as a solidifying agent.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.90-96
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• 2000

The optimum cooking conditions for large scale continuous gas cooker were studied with three varieties of rice. Optimum soaking time for the cooker was estimated to be 30 min at cooking temperature above $20{\circ}C$, while 60 min at cooking temperature below $10{\circ}C$. The ratio of water-to-milled rice giving the best eating quality was founded to be $1.41{\sim}1.48$, and corresponding moisture content of cooked rice ranged from 60 to 62% for different rice varieties. The optimum ratio of water to milled rice. (Chucheong) decreased from 1.50 to 1.37 with increase in the amount of milled rice from 4.0 to 6.5 kg in a cooking vessel. However, actual water uptake by rice (g water absorbed per g rice) on cooking was nearly constant value of 1.13, which means that evaporated water during cooking increases with decreasing the amount of rice in a cooking vessel.

• Solar Energy
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• v.10 no.2
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• pp.38-43
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• 1990

The present study was to investigate the use of a phase change material for hydronic radiant floor heating. Two identical unit test cells sized $1.8m^L{\times}1.8m^W{\times}1.8m^H$ were built and installed with specially designed $1.6cm^T{\times}9cm^W{\times}80cm^H$ aluminum Ondol-panels holding 1.25kg of calcium chloride hexahydrate(CCH) each. It was found that the Ondol-panel with CCH reduced the room temperature fluctuations and maintains the phase changing temperature for considerably long duration, $2{\sim}4$ times of heating hour, over no-CCH one.

• Korean Architects
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• no.5 s.65
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• pp.58-60
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• 1974

연약지반에 있어서 생석회를 사용한 토질 안정처리 공법중 Pack-Lime 공법에 대하여 기술코자 한다. 본 공법은 생석회를 분말 그대로 투입함으로서 Casing 내의 물과 생석회와의 급격한 수화작용으로 투입과정에서 분말의 비산과 소정양의 투입이 불확실한 흡점을 보강하기 위하여 특수 포장지인 흡수성 포대에 생석회를 넣어 Unit로 만들어 Casing내에 투입하여 연속된 생석회 말뚝을 축조하는 공법이다.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.188-193
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• 1998

The authors examined the variations of environmental factors, the distributions of cyanobacteria, heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica according to development and extinction of cyanobacterial bloom at a site in Daechung Dam reservoir. And certified the relationship between each other. Water temperature variated in a typical pattern. pH and concentrations of dissolved oxygen and chlorophylla was high in bloom period, and lowered with the decline of bloom. Phosphorus played as a growth-limiting factor at this study site. Total nitrogen concentration increased during blooming period, which indicated that nitrogen has been fixed by aquatic organisms such as cyanobacteria. Cyanobacteria distributed from June 17, and such cyanobacterial species as Anabaena spp., Aphanizomenon spp., Microcystis spp., Oscillatoria spp. and Phormidium spp. was detected during study period. Anabaena spp. distributed relatively highly distributed from July 23 to September 22, and disappeared completely at September 29. Heterotrophic bacterial and cyanobacterial populations varied inverse-proportionally. There was a relevancy between the variations of Anabaena spp., heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica. Microorganisms that inhibit the growth of Anabaena cylindrica distributed from early growth phase of Anabaena spp. population to immediately after the extinction of Anabaena spp. With the population of Anabaena cylindrica growth-inhibiting microorganisms decreasing, increases of heterotrophic bacterial population followed it. Thease results indicate that microorganisms have a part in the extinction of cyanobacterial bloom, especially at its destroying period.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.724-728
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• 1995

Chemical compositions of dried Auricularia polytricha mushroom were analyzed when the dried mushroom were soaked in distilled water at different soaking condition. Physicochemical properties of soaked mushroom were investigated. Compositions of chemical components were 12.6% crude protein, 2.1% crude fat, 6.7% crude fiber and 6.2% ash. The contents of Ca, K, Mg were higher than those of other minerals in the sample, but Mn and Ni were of little quantities. The major amino acids of the sample were found to be aspartic and glutamic acid. The increase in the soaking time and temperature increased the ratio of water uptake, amount of water soluble solid, browning and pH value in the soak water. Ribonucleotide contents of the sample after soaking decreased depending on soaking time and temperature.

• 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.28 no.6
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• pp.679-684
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• 2017

Hydrated liquid crystalline vesicles incorporating a edge activator, which confers flexibility to the vesicle membranes, were prepared and niacinamide was encapsulated in them. The formation of liquid crystalline phases and their thermal phase transitions were investigated by polarized optical microscopy and differential scanning calorimetry (DSC), respectively. Droplet sizes of the vesicles were reduced to several tens of nanometers by incorporating edge activators, such as sodium deoxycholate, lysolecithin, or polysorbate 80. The amount of niacinamide permeated into a pig skin increased greatly using the hydrated liquid crystalline vesicles compared to the case where niacinamide was applied in an aqueous solution state. The vesicles incorporating 10% sodium deoxycholate increased the amount of niacinamide permeated nearly four times. These results suggest that edge activators are effective in improving the skin permeability of vesicles.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.78-85
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• 2020

Shotcrete concrete is generally used in the form of ready-mixed concrete products using type I ordinary portland cement(hereinafter referred to as OPC) and about 5% of accelerator mixed separately in the field. In this study, we tested the effect of OPC fineness and SO₃ content on a penetration resistance, compressive strength of binder for shotcrete using calcium aluminate type accerlerator. And we analysed hydrates and pore structure effects on mortar performance. In the future, it is expected to be useful for manufacturing optimized OPC as a binder for shotcrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.86-93
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• 2020

Shotcrete concrete is generally used in the form of ready-mixed concrete products using type I ordinary portland cement(hereinafter referred to as OPC) and about 5% of accelerator mixed separately in the field. In this study, we tested the effect of addition of slag powder(SP) and limestone powder(LSP) on a penetration resistance, compressive strength of binder for shotcrete using calcium aluminate type accerlerator. And we analysed hydrates and pore structure effects on mortar performance. In the future, it is expected to be useful for manufacturing optimized composite cement as a binder for shotcrete.