• 한국축산시설환경학회지
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• 제6권2호
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• pp.73-81
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• 2000

A two-phase anaerobic digestion system for the treatment of swine waste was constructed in a commercial hog farm. The digester system was composed of 4 major units; slurry storage pit, acidogenic digester, methanogenic digester and sedimentation pit. A biogas boiler unit was also attached to maintain the digester temperature of 37$^{\circ}C$. Substrate lading was made with 2hr-interval by pumping about 2.1$m^3$ of slurry type swine waste from the slurry pit into the acidogenic digester, which corresponds to hydraulic retention time of 4 days for the acidogenic digester and of 11 days for the methanogenic digester. Digester temperature were well maintained as the set temperature of 37$^{\circ}C$ in the methanogenic digester, while the temperature in the acidogenic digester showed around 34$^{\circ}C$. pH also showed a steady-state results of 7.3 in the acidogenic digester and of 7.6 in the methanogenic digester during the operation period. Average biogas production rate was 0.66$m^3$/$m^3$ digester volume. Reduction rate of total solid and volatile solid were 42.8% and 5.8%, respectively. Total nitrogen and ammonia nitrogen were not reduced during the anaerobic fermentation, however, most of VFAs seemed to be converted to the biogas,. These fermentation performance data may suggest that he newly developed a two-phase anaerobic digester for the swine waste treatment worked so successfully.

• 한국세라믹학회지
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• 제46권2호
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• pp.137-145
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• 2009

A remarkable improvement of the productivity in barium titanate by slurry spray pyrolysis process was realized by supplying solid source slurry into the rector. The produced barium titanate powders showed uniform powder properties, and reproducibility with higher tetragonality in the range of 80$\sim$200 nm, case by case. The secondary calcination experiments of the as-prepared powders by spray pyrolysis revealed that the powders as-prepared over 700$^{\circ}C$ showed perfectly different behavior with the lower temperature's ones and the solid state reaction’s case. The result was discussed in terms of the reaction mechanism based on the activation energy analysis.

• 한국분말재료학회지
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• 제21권4호
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• pp.266-270
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• 2014

Metal foams have a cellular structure consisting of a solid metal containing a large volume fraction of pores. In particular, open, penetrating pores are necessary for industrial applications such as in high temperature filters and as a support for catalysts. In this study, Fe foam with above 90% porosity and 2 millimeter pore size was successfully fabricated by a slurry coating process and the pore properties were characterized. The Fe and $Fe_2O_3$ powder mixing ratios were controlled to produce Fe foams with different pore size and porosity. First, the slurry was prepared by uniform mixing with powders, distilled water and polyvinyl alcohol(PVA). After slurry coating on the polyurethane(PU) foam, the sample was dried at $80^{\circ}C$. The PVA and PU foams were then removed by heating at $700^{\circ}C$ for 3 hours. The debinded samples were subsequently sintered at $1250^{\circ}C$ with a holding time of 3 hours under hydrogen atmosphere. The three dimensional geometries of the obtained Fe foams with an open cell structure were investigated using X-ray micro CT(computed tomography) as well as the pore morphology, size and phase. The coated amount of slurry on the PU foam were increased with $Fe_2O_3$ mixing powder ratio but the shrinkage and porosity of Fe foams were decreased with $Fe_2O_3$ mixing powder ratio.

• 한국축산시설환경학회지
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• 제19권2호
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• pp.101-108
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• 2013

This study was to investigate the effect of addition levels of odor reducing contents on reducing the concentration of odorous compounds. Slurry treatments included three levels mixture of horseradish powder (HP), mushroom waste (MW) and probiotics powder (PP), and non-treatment control (n=4 each group). Levels of odorous compounds were measured from the liquid slurry incubated in room temperature ($20{\sim}25^{\circ}C$) for 2 wk in chamber whose structure is similar to slurry pit. Concentration of phenols and indoles was lower (p<0.05) in level 1, which was mixed HP 0.01%, MW 0.4% and PP 0.004% (98.69, 1.87 ppm) compared to control. Short chain fatty acid (SCFA) and branched chain fatty acid (BCFA) was lowest (p<0.05) level 1 (6,557, 1675 ppm). Taken together, lower level are effective in reducing odorous compounds in pig slurry.

• Animal Bioscience
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• 제35권2호
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• pp.308-316
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• 2022

Objective: This study was conducted to determine reduction of various odorous materials from a swine farm equipped with a continuous pit recirculation system (CPRS) with aerobically treated liquid manure. Methods: The CPRS is used in swine farms in South Korea, primarily to improve air quality in pig houses. In this study, CPRS consists of a manure aerobic treatment system and a fit recirculation system; the solid fraction is separated and composted, whereas the aerobically treated liquid fraction (290.0%±21.0% per day of total stored swine slurry) is continuously returned to the pit. Four confinement pig barns in three piggery farms were used; two were equipped with CPRS and the other two operated a slurry pit under the slatted floor. Results: All chemical contents of slurry pit manure in the control were greater than those of slurry pit manure in the CRPS treatment (p<0.05). Electrical conductivity and pH contents did not differ among treatments. The biological oxygen demand of the slurry pit treatment was greater than that of the other treatments (p<0.05). Total nitrogen, total phosphorus, and ammonia nitrogen contents of the slurry pit treatment were greater than those of other treatments (p<0.05). Odor intensity of the CPRS treatment was lower than that of the control at indoor, exhaust, and outside sampling points (p<0.05). The temperature and carbon dioxide of the CPRS treatment in the pig barn was significantly lower than those of control (p<0.05). All measured odorous material contents of the CPRS group were significantly lower than those of the control group (p<0.05). Conclusion: The CPRS application in pig farms is considered a good option as it continuously reduces the organic load of animal manure and lowers the average odorant concentration below the threshold of detecting odorous materials.

• 한국수소및신에너지학회논문집
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• 제31권3호
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• pp.276-283
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• 2020

Alcohol-based solvents including ethanol (EtOH) and tert-butyl alcohol (TBA) are investigated instead of isopropanol (IPA), which is a common solvent for polytetrafluoroethylene (PTFE), as an alternative solvent for preparing the catalyst slurry with PTFE binder. As a result, the performance at 0.2 A/㎠ from the single cells from using catalyst slurries based on EtOH and TBA showed very similar value to that from the slurry using IPA, which implies the EtOH and TBA can be used as a solvent for the catalyst slurry. It is also confirmed by the very close values of the total resistance of the membrane electrode assemblies from the slurries using different solvents. In the energy dispersive spectrometry (EDS) image, the shape of crack and dispersion of PTFE are changed according to the vapor pressure of the solvent.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_4호
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• pp.157-164
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• 2001

The performance of fluidized-bed reactor with Photomedia, immobilized TiO$_2$ onto the porous ceramic ball using a sol-gel method has been studied in this work. A simple model substrate, dilute Rhodamine B (RhB), was decolorized at room temperature. For the purpose of comparison, the slurry reactor and the Inner Wall Coated Reactor (IWCR) were used. The aim of this work was to develop the photocatalytic fluidized bed reactor (PFBR) through contrasting the photodegradability of various reactors such as the TiO$_2$slurry reactor, the inner-wall coated reactor (IWCR). In this study, the RhB was decolorized in three types of reactor. Even though the reaction rate constant of PFBR was lower than that of slurry reactor, PFBR had the advantages of preventing the wash-out of photocatalyst, so it can be operated continuously.

• 한국대기환경학회지
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• 제12권4호
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• pp.449-457
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• 1996

The main purpose of this study was to investigate sulfur dioxide removal performance of flue gas desulfurization system utilizing a Spray Absorption/Drying Reactor. In this system, the size of droplets was considered the most significant factor and tested using a PDA system. Lime slurry flow rate, operating temperature, calcium/sulfur (Ca/S) ratio and applied air pressure were selected as major operation variables and tested/analyzed in terms of system performance. The results are as follows. 1. The $SO_2$ removal efficiencies were 49%, 74%, 85% for Ca$(OH)_2$ slurry flow rate of 10, 20, 30 ml/min, which implies that the increase of slurry flow rate improves removal efficiency. The optimum slurry flow rate in this study was, however, considered 20 ml/min because of constraints of system troubles and absorbent utilization. 2. As Ca/S ratio increased, $SO_2$ removal efficiency was observed to increase. 3. As air pressure, at the atomizing nozzole, increased from 3 to 5 $kg/cm^2, SO_2$ removal efficiency increased from 74% to 80%, because of droplet size reduction due to pressure increase during atomizing process and the increase of surface area, helping mass transfer between gas and liquid phase.

• 한국분말재료학회지
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• 제27권3호
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• pp.193-197
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• 2020

Porous Cu-14 wt% Co with aligned pores is produced by a freeze drying and sintering process. Unidirectional freezing of camphene slurry with CuO-Co₃O₄ powders is conducted, and pores in the frozen specimens are generated by sublimation of the camphene crystals. The dried bodies are hydrogen-reduced at 500℃ and sintered at 800℃ for 1 h. The reduction behavior of the CuO-Co₃O₄ powder mixture is analyzed using a temperature-programmed reduction method in an Ar-10% H₂ atmosphere. The sintered bodies show large and aligned parallel pores in the camphene growth direction. In addition, small pores are distributed around the internal walls of the large pores. The size and fraction of the pores decrease as the amount of solid powder added to the slurry increases. The change in pore characteristics according to the amount of the mixed powder is interpreted to be due to the rearrangement and accumulation behavior of the solid particles in the freezing process of the slurry.

• 한국주조공학회지
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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.