• Polymer(Korea)
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• v.32 no.3
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• pp.213-218
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• 2008

About 17% of historical properties in Korea were made of stones and most of them are exposed to weathering, as such that discoloring, cracking, and shattering occur from physical, chemical, mechanical, and biological effects due to outdoor placement. Proper treatments for conservation are necessary to prevent the weathering damage and to retain the original shape of stones. MMA, an acrylic monomer having low viscosity can be impregnated deep inside stones by consecutive compression and decompression process in a pressurized vessel. After the polymerization of MMA impregnate, the space inside of the stone was filled with PMMA. It is expected that water repellent and weather resistant properties will be improved because of the improved bonding of constituent materials in stones. In this study, moisture absorption, chemical resistance, and mechanical property of two domestic granites were examined after treating them with MMA for the purpose of determining the conservation value of this method that was possibly useful to the conservation of stone cultural assets.

• Nuclear Engineering and Technology
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• v.5 no.4
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• pp.310-320
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• 1973

The sorption and fixation of cesium in dilute solutions by vermiculite saturated with Na or K were studied in order to investigate any possibibty of its use in radioactive effluent treatment. The cesium sorbed by vermiculite with the increase in pH is attributed to the increase of sorption surface as a result of the dispersion. The increased cesium sorption by Na-vermiculite is due to the different sorption rates by the different exchange sites : external surface and internal surface. It is shown that the larger amount of sorbed cesium was extracted by KCI rather than with any other extractants. It is suggested that the fixation of cesium by vermiculite occurs at the crystal edge where Cs may replace K. Domestic vermiculite is a valuable material for use in the cesium sorption and fixation, and might be useful as a good packing material outside the tank of highly radioactive liquid waste. And from these results one could suggest that the artificial alteration of the biotite to vermiculite might be occurring by treating with NaCl.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.760-766
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• 2008

The characteristics of heat transfer and pressure drop of several different porous materials which can be used as inserts inside solar volumetric air receivers were experimentally investigated. Generally, porous materials were inserted into solar volumetric air receivers to increase the thermal performance. In the present work, honeycomb (diameter: 100 mm, thickness: 30 mm), laminated mesh (diameter: 100 mm, thickness: 1 mm) are considered as the inserts for the experiment. The experimental apparatus consists mainly of a cylindrical ceramic duct as a receiver and an electric heater as an energy source. This system is an intake open loop, which used as air of working fluid. The temperatures inside the ceramic tube are measured by thermocouples, which are installed at each layer of the porous materials. The pressure-drop experimental apparatus is fabricated alike the above experimental equipment. An acrylic tube is used like as the ceramic tube, which has the same specifications of the ceramic tube. The pressure drop of porous materials inserted in the acrylic tube is measured between front and rear of those by transmitter. The results show that the laminated mesh surpasses the honeycomb of heat transfer and pressure drop increase as the porous material thickness and Reynolds number.

• Korean Journal of Food Science and Technology
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• v.8 no.2
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• pp.85-89
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• 1976

The separation and determination of dicarbonyls such as diacetyl, methylglyoxal and triose reductone in their mixed aqueous solution were carried out by means of gas chromatography with transformation of these compounds into quinoxaline derivatives with o-phenylenediamine. A column used for this experiment was consisted of Celite 545 (80-100 mesh) coated with 5% Silicon Gum SE-30. The column temperature was $180^{\circ}C$. It is desirable that this approach will be applicable to dicabonyl study in gas chromatographic determination.

• Journal of Life Science
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• v.13 no.3
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• pp.365-373
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• 2003

Instead of deodorization appararus of fish oil, an adsorbent such as activated charcoal, activated alumina, silicagel, bamboo charcoal was packed in column alone or mixed with preparative ratio, and then test the effective deodorization with bleaching. In the progress of degumming, the effective method was 18 ml of 2.5% oxalic acid per 100m1 of crude large anchovy oil. The optical condition to deacidified was treating for 30 min at $40^{\circ}C$ with 2.5% sodium hydroride solution. The effective deodorization was added with 3% silicagel under the alone treating adsorbent, and mixed treating was 30% activated alumina and 10% silicagel but added to green tea powder was not effective. The major fatty acid of total lipid were 16:0, 20:5n-3, 18:1n-9, 16:1n-7 and 22:6n-3 after treatment of degumming, deacidfication and deodorizing in the large anchovy oil. The oxidative stability of refined anchovy oil added to $\alpha$-tocopherol was validated 20 days under the control, and 30 days in the case of $\alpha$-tocopherol. The 0.01% $\alpha$-tocopherol was more effective than 0.02% $\alpha$-tocopherol.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.5
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• pp.445-452
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• 2015

A tubular packed bed reactor for the steam-$CO_2$ combined reforming of natural gas to produce the synthesis gas of a target $H_2/CO$ ratio 2.0 was simulated. The effects of the reactor dimension, the feed gas composition, and the gas feeding temperature upon the possibility of coke formation across the catalyst bed were investigated. For this purpose, 2-dimensional heterogeneous reactor model was used to determine the local gas concentrations and temperatures over the catalyst bed. The thermodynamic potential distribution of coke formation was determined by comparing the extent of reaction with the equilibrium constant given by the reaction, $CH_4+2CO{\Leftrightarrow}3C+2H_2O$. The simulation showed that catalysts packed in the central region nearer the entrance of the reactor were more prone to coking because of the regional characteristics of lower temperature, lower concentration of $H_2O$, and higher concentration of CO. With the higher feeding temperature, the feed gas composition of the increased $H_2O$ and correspondingly decreased $CO_2$, or the decrease in the reactor diameter, the volume fraction of the catalyst bed subsequent to coking could be diminished. Throughout the simulation, reactor dimension and reaction condition for coking-free operation were suggested.

• KSBB Journal
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• v.21 no.3
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• pp.188-193
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• 2006

A new type of biofilter, a rotating drum biotrickling filter(RDBF), was developed and operated for the removal of styrene from industrial waste gas. The porous polyurethane foam sheet was used as a packing materials for the RDBF and a pure culture of Gram-positive bacterium Brevibacillus sp. SP1 was used as an inoculum. The reactor showed a short start-up period of 18 days, during which uniform biofilms were developed on the packing. During a steady operation at an incoming styrene concentration of $200ppm_v$ and a retention time of 0.5 min, a high and stable removal of styrene over 95% was observed. The maximum elimination capacity was estimated to be $125g/m^3{\cdot}hr$. The outstanding performance was attributed to an efficient gas-liquid mass transfer and the appropriate supply of nutrient solution to the biofilm microorganisms on the packing by the rotation of the drum.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.28-33
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• 2006

A sewage was treated using a horizontal flow zeolite-filled reed bed. The sewage from the student dormitory of Changwon National University was fed into the reed bed for 10 minutes every 6 hours at the hydraulic load of $314L/m^2$ day. The filtering height of the reed bed was 100 cm and the zeolite mixture was filled in the reed bed. The mixture consisted of the same volume of two types of zeolite : $0.5{\sim}1mm$ and $1{\sim}3mm$ in diameter. Annual average removal efficiency was SS $88.5%,\;COD_{cr},\;86.1%,\;COD_{Mn}\;81.0%,\;T-N\;48.6%,\;NH_4^+-N\;97.1%$ and T-P 42.8%. T-N of effluent was mostly $NO_3^--N$ and the concentration of $NO_2^--N$ in effluent was lower than 0.1 mg/L. All removal efficiencies did not show a remarkable seasonal change.

• Journal of the Korean earth science society
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• v.29 no.7
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• pp.551-558
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• 2008

The Soowang deposits occur in the quartz veins that were filled fissures in the middle Cretaceous porphyritic granite and/or the Precambrian Sobaegsan gneiss complex. Paragenetic studies suggest that the vein filling can be divided into four identifiable stages. Sphalerites were deposited by the cooling fluids at stages I, II, and III. The results of microscopic observation and EPMA analysis suggest that the chalcopyrite dots and disease in sphalerite are replacement products by later hydrothermal solution at the early stage III. The inferred processes of chalcopyrite disease are as follows: (1) Fe enrichment to the margins and along the cracks of the Fe-poor sphalerite by Fe-rich solution, (2) Formation of chalcopyrite dots in the Fe-enriched sphalerite formed at the stage II, and Fe reduction of sphalerite near the chalcopyrite dots by Cu-bearing solution, (3) Formation of "chalcopyrite disease" penetrating the compositional zoning of sphalerite at the early stage III.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.654-658
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• 2012

In this work, the properties of an organic-inorganic hybrid insulating material using an inorganic filler and polyurethane foam with different foaming conditions were investigated. At weight ratios of polyol and isocyanate of 1 to 1.2 good foaming properties were noted. In addition, an addition of 0.4 g of water, 0.1 g of surfactant, and 0.1 g of catalyst with respect to the composites of polyol at 5 g and isocyanate at 6 g showed the lowest apparent density and thermal conductivity. The pore size was smaller in the organic-inorganic hybrid foaming body with an increase in the $CaCO_3$ addition amount. Moreover, the apparent density and thermal conductivity were increased when the added amount of $CaCO_3$ increased. Increasing the amount of $CaCO_3$ powder is expected to improve the flame retardant capabilities; however, doing this tends to increase the apparent density and thermal conductivity.