• Journal of Korea Foundry Society
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• 제28권6호
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• pp.282-287
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• 2008

The effect of CaO mold on the formation of reaction layer was investigated. CaO mold was prepared by mixing of Colloidal silica($NALCO^{(R)}$ 1130) and an $ZrO_2$, CaO at room temperature. The dried at $20{\pm}3^{\circ}C$, 75% humidity for 12hrs. Sample was prepared from the Cp-Ti(grade-2) and melted by high frequence induction melting system in the vacuum condition. The react ion layer of Ti was confirmed by optical microscopy, microhardness(Hv) and X-ray diffraction. Thickness of reaction layer using the CaO stabilized ZrO2 was thinner than the CaO added ZrO2. And thickness of reaction layer were decreased with decreasing pH of slurry. CaO addition in the slurry could not controlled reaction between molten Ti and investment mold. On the other hand, the CaO chemical bonded ZrO2 by stabilization treatment could controlled reaction between molten Ti and investment mold.

• Journal of Animal Environmental Science
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• 제7권2호
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• pp.111-118
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• 2001

This study was performed for measuring the emission of greenhouse gases, $CH_4,\;N_2O$, from the composting process for pig slurry. For the experiment the benchscale pilot plant was designed by 1$m^3$ volume reactor with a closed type and operated; sawdust 142kg filled before input slurry, slurry about 10~20l inputed per day (total 380l), air supplied 5l/min for 24 hours, mixing time 10 min./day and 1 time a day. From the total experiment period(30days), the amount of VS degradation and emission $CH_4$, $N_2O$ were 10.9kg-VS and 1,582.4g-$CH_4$, 68.1g-$N_2O$ respectively. Based on VS inputed the emission of $CH_4$, $N_2O$ were 15.3(g-$CH_4$/kg-V $S_{input}$), 0.7(g-$N_2O$ /kg-V $S_{input}$), and based on VS degradated were 145.2(g-$CH_4$/kg-V $S_{removed}$), 6.2(g-$N_2O$ /kg-V $S_{removed}$).

• Journal of the Korean Ceramic Society
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• 제40권12호
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• pp.1183-1188
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• 2003

LCP (Liquid Crystal Polymer)/BT(BaTiO$_3$) composite was prepared by mixing LCP varnish and BT slurry. And the effect of the composition of LCP/BT composites and the size of BT powder on dielectric properties of LCP/BT composite were investigated. The dispersion properties of BT slurries were also studied as a function of volume fraction of dispersant, GLYMO (3-glycidyloxypropyltrimethoxysilane) added to various sized BT powders. The quantity of optimum dispersant in BT slurry decreased with an increase of BT powder size because of the decrease of specific surface area of BT powder. LCP/BT composite sheet was prepared by tape-casting method with mixing BT slurry and LCP varnish. The dielectric constant of the composites increased from 34.3 to 44.1 and their dielectric loss increased from 0.05 to 0.063 as the size of BT powder increased from 100 nm to 500 nm.

• Journal of the Korean GEO-environmental Society
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• 제17권12호
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• pp.45-54
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• 2016

In this study, the construction method of new underground continuos impervious wall that the bentonite slurry keeps the stability of excavated trench and the mixture of cement and bentonite plays a role as a constituent of impervious wall in the trench. The merit of homogeneity of the method so called as a cement-bentonite slurry wall enables to accurately make an estimation of hydraulic conductivity of the walls compared with that by other general grouting methods and to verify their waterproof efficiency without difficulty at the design stage. The use of cement-bentonite slurry walls for the containment of groundwater flow has also proven a cost-effective impervious wall technology by employing the simple combination of construction equipments and easy and fast construction procedures. The engineering characteristics of cement-bentonite impervious wall obtained by carrying out the laboratory experiments under various conditions. This study reveals the effect of variation of constituent materials and their mixing methods (Water-Cement-Bentonite) on the engineering characteristics of a composition. Also, this study makes some recommendations on the optimum mixing ratio and mixing sequence for the best quality at the site. That is the most important factors to estimate the construction cost and design of the technique. The comparison is lastly made to evaluate the effect of ordinary Portland and blast furnace slag cement as a bonding material on the behavior of impervious walls.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.144-147
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• 2003

In this study, the mass transfer behaviors of phenanthrene, anthracene, and pyrene in soil slurry reactor (SSR) using two-liquid phase (TLP) system were investigated. The mass transfer ratio and rate of PAH in the TLP system using light paraffine oil, which has the highest solubility of PAH, were influenced by the amount of light paraffine oil and mixing speed. When the amount of light paraffine oil decreased from 15 % to 2.5 % (v/v), the mass transfer ratio of anthracene decreased significantly compared with that of phenanthrene and pyrene. As mixing speed increased, the initial mass transfer rate of PAH within 1 day was enhanced. However, each final mass transfer ratio of three PAHs after 5 day was similar irrespective of mixing speed.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.529-532
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• 2004

As the purpose of this study is a research of series to obtain fundamental data on the development of the product of foamed concrete using bottom ash for various applications in the field, the main purpose is the light weight of product of concrete. In this experiment, method of mixing of foam is very important because it control specific gravity and strength of the product. As the test results, it was found that regardless of mixing method the grower the concentration of foaming agent the lower the specific gravity and the compressive strength of the specimen especially pre-foaming method. From a strength point of view, we knew that mix-foaming method and steam curing is efficient to obtain a adequate compressive strength of foamed concrete.

• Korean Journal of Materials Research
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• 제25권1호
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• pp.27-31
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• 2015

This paper proposes a novel way of fabricating aligned porous Sn by freeze-drying of camphene slurry with stannic oxide ($SnO_2$) coated Sn powders. The $SnO_2$ coated Sn powders were prepared by surface oxidation of the initial and ball-milled Sn powders, as well as heat treatment of tin chloride coated Cu powders. Camphene slurries with 10 vol% solid powders were prepared by mixing at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing the slurry was done in a Teflon cylinder attached to a copper bottom plate cooled at $-25^{\circ}C$. Improved dispersion stability of camphene slurry and the homogeneous frozen body was achieved using the oxidized Sn powder at $670^{\circ}C$ in air after ball milling. The porous Sn specimen, prepared by freeze-drying of the camphene slurry with oxidized Sn powder from the heat-treated Sn/tin chloride mixture and sintering at $1100^{\circ}C$ for 1 h in a hydrogen atmosphere, showed large pores of about $200{\mu}m$, which were aligned parallel to the camphene growth direction, and small pores in their internal walls. However, $100{\mu}m$ spherical particles were observed in the bottom part of the specimen due to the melting of the Sn powder during sintering of the green compact.

• Journal of Animal Environmental Science
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• 제5권3호
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• pp.189-196
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• 1999

Anaerobic digestion is a naturally occuring microbial process involving the decomposition of organic materials such as livestock manure. This study explores the effect of the operating conditions, HRT (Hydraulic Retention Time) and feeding frequency on treatment efficiency for digestion of pig slurry, which has been one of most difficult organic waste for proper treatment in livestock production industry in Korea at the present time. The pilot-scale CSTR of 5 m3 in volume was designed. manufactured, and operated at the temperature of 35$\pm$1$^{\circ}C$. The digester was designed to hydraulically stir for complete mixing and to supply heat from the water bath to maintain mesophilic temperature. The HRT of the digester for Test 1 and Test 2, and Test 3 was set for 17 days and 13 days respectively and pig slurry was fed once a day with 300$\ell$ each for Test 1 and Test 3, while twice with 150$\ell$each for Test 2. Test 2 showed better performance by increase of 4% in VS removal efficiency and 5% in biogas production rate. This is mainly attributed to smaller temperature drop by feeding frequently with half amount, which eventually led to lesser impact on anaerobic mocrobes in the digester. Test 2 maintained optimum pH 7.8 which uplifted the activaton of sulfur-reduction bacteria, alkalinity of around 4,000mg/$\ell$, VA of over 3,000mg/$\ell$ for whole period of experiment. Further research may require to provide the practical operation strategy of anaerobic treatment system for treatment of pig slurry.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제20권5호
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• pp.1735-1742
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• 1996

An entrained flow gasifier simulating the cold mode was tested to estimate its performance for coal gasification and flow characteristics with a developed high speed impinging jet nozzle. The burner was designed for high temperature and high pressure(HTHP) conditions, especially for IGCC(Integrated Coal Gasification Combined Cycle). In order to get proper size of droplets for high viscous liquid such as coal slurry, atomization was achieved by impacting slurry with high speed (over 150m/sec) secondary gas (oxygen/or air)/ Formed water droplets were ranged between 100.mu.m to 20.mu.m in their sizes. The flow characteristics in the gasifier was well understood in mixing between fuel and oxidizer. Both external and internal recirculation zones were closely investigated through experimentation with visualization and numerical solutions from FLUENT CODE.

• Journal of the Korean Ceramic Society
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• 제34권11호
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• pp.1173-1181
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• 1997

Effects of particle size distribution of alumina ceramics on behaviors of tape casting were investigated with emphases on the rheological characteristic of slurry, green density, green sheet strength, and sintering density. For the control of particle size distribution of alumina, the commercial grade low soda alumina, which had different mean particle size of 3.58 ${\mu}{\textrm}{m}$ and 0.42 ${\mu}{\textrm}{m}$, were chosen and blended together. As results, the mixing of 80 wt% fine powder and 20 wt% coarse powder(designated to FC20) led to the increase of packing density and strength of green sheet, and made it easy to handle during processing without lowering of sintering density. Besides, the pseudoplastic behavior of slurry decreased with increase of the fraction of coarse alumina powder.