• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.188-193
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• 2006

Synthesis of Boehmite particles were performed through the precipitation of aluminium nitrate ($Al_{3}(NO_{3})_3{\cdot}9H_{2}O$) with ammonia water ($NH_{4}OH$) by changing solution pH, mixing procedure, temperature, and feeding flux. The influence of the synthesis condition, which affected on the pH range of the Boehmite formation, particle morphology and pore property, was investigated. The Boehmite particles were formed in the reaction solution of pH 7.5~9. The particles prepared by P2jet type which maintained the pH uniformly during the precipitation resulted in homogeneous particles and pores because of the constant concentration of the reacted ion in the solution. It was resulted in the improvement of the specific surface area and pore volume of the particle at the same time. With the increasing of temperature and the decreasing of the feeding flux, it was occurred the large specific surface area and pore volume. Also it was presented the fibrillar shaped particles upper $60^{\circ}C$ of the reaction temperature. In this study, the optimal condition of the porous Boehmite was in P2jet type with $90^{\circ}C$ of reaction temperature and 2.5 mL/min of the feeding flux. At this time, the specific surface area, pore volume, and average pore size was $385.46m^2/g$, 1.0252 mL/g, 10 nm, respectively.

• Journal of Soil and Groundwater Environment
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• v.12 no.3
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• pp.75-80
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• 2007

This study evaluated groundwater quality around an uncontrolled landfill in W sity, Korea, which was monitored for about two years (2005-2006). Parameters of concern include redox-sensitive indicators such as pH, DO, EC, ORP, DOC (dissolved organic carbon), NH3, NO3 and SO4. About 10 years have elapsed after closing dumping of municipal wastes in the landfill. Leachates showed widely varying concentrations in COD(136${\sim}$263 mg/L), T-N(121${\sim}$186 mg/L), and NH3-N(14${\sim}$369 mg/L). Groundwater at the immediate downgradient of the landfill showed weakly acidic pH condition but very high levels of EC (3,000-4,000 ${\mu}S/cm$), which indicated that the groundwater was largely affected by the landfill leachate. Cl, a conservative ion, showed over 200 mg/L at the landfill border, but a gradually decreasing level with distance from the landfill, representing dispersion and dilution (natural attenuation) due to mixing with surrounding groundwater and replenished rainwater. Redox potential showed negative value at the landfill border but it increased up to 350 mV at downgradient wells, which indicated conversion of redox condition from reducing oxic ones. Ammonia, was largely enriched at most of the monitoring wells and its level greatly exceeded drinking water standard. In summary, all the parameters evidenced occurrence of natural attenuation with distance and with time but further monitoring is still required.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.184-190
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• 2013

Cave environment provides special ecosystems for evolution of lives distant from surface environments. We investigated bacterial and archaeal communities of wall biofilm obtained from of a volcanic cave (Daesubee) in Jeju, Republic of Korea. Bacterial and archaeal 16S rRNA genes were PCR-amplified and sequenced using pyrosequencing technologies. Unique prokaryotic communities with low diversities were observed. The main bacterial sequences (ca. 83% of total reads) were affiliated with Pseudonocardia mongoliensis of phylum Actinobacteria and clustered with clones obtained from various caves. Reflection of light on the wall surface of cave might be caused by formation of beads of water caused by hydrophobic filaments of actinobacterial colonies. Main archaeal sequences (ca. 65.7% of total reads) were related with those of I.1a-Associated group of phylum Thaumarchaeota. The sequences were related with that of Candidatus Nitrosotalea devanaterra which was known to oxidize ammonia under acidic condition (ca. pH 5.0). Nutrients leached through volcanic soils contribute formation of unique microbial communities of wall biofilm of cave Daesubee.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.3
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• pp.354-362
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• 2018

Objective: Wheat is an alternative to corn silage for ruminant feeding in northern China. This study examined the effects of harvest time and added molasses on nutritional content, ensiling characteristics and in vitro degradation of whole crop wheat (WCW). Methods: Fresh WCW at the milk-ripe stage was harvested at 0700 h (i.e., in the morning [Mo]) and 1700 h (i.e., in the afternoon [Af]), and then immediately used to prepare silage and make hay. Commercial molasses was added to Af WCW at 0%, 2%, 4%, and 6% (fresh weight) proportions. The WCW treated with molasses was mixed thoroughly prior to ensiling. Results: Dry matter (DM), neutral detergent fiber, water soluble carbohydrate (WSC) content (p<0.01), accumulative gas production in 72 h ($GP_{72h}$, 77.46 mL/g vs 95.15 mL/g) and dry matter disappearance in vitro (69.15% vs 76.77%) were lower (p<0.05), while crude protein (CP) content was higher for WCW silage (WCWS) compared to WCW (p<0.01). The propionic acid and butyric acid concentrations in WCWS from Mo WCW were 1.47% and 0.26%, respectively. However, the propionic and butyric acid concentrations were negligible, while the ammonia nitrogen/total nitrogen ($NH_3-N/TN$, p<0.01) concentration was lower and the rate of gas production at 50% of the maximum (17.05 mL/h vs 13.94 mL/h, p<0.05) was higher for Af WCWS compared to Mo WCWS. The incubation fluid's $NH_3-N$ concentration was lower in WCWS and Af WCW compared to Mo WCW (p<0.05). The CP and WSC content increased with increasing molasses levels (p<0.05). Furthermore, the pH (p<0.01) and time when gas production was 50% of the maximum (2.78 h vs 3.05 h, p<0.05) were lower in silage treated with 4% molasses than silage without molasses. Conclusion: Harvesting wheat crops in the afternoon and adding molasses at 4% level to WCW optimally improved ensiling characteristics, leading to well-preserved silage.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.6
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• pp.949-956
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• 2020

Objective: This study was conducted to confirm the effects of new inoculants producing-antifungal or esterase substances on rye silage and its rumen fermentation indices by comparing wild with mutated types. Methods: Rye harvested at dough stage was ensiled into 3 L mini bucket silo (1 kg) for 90 d in triplicate following: distilled water at 20 μL/g (CON); Lactobacillus brevis 100D8 (AT) and its inactivation of antifungal genes (AT-m) at 1.2×10⁵ cfu/g, respectively; and Leuconostoc holzapfelii 5H4 (FD) and its inactivation of esterase genes (FD-est) at 1.0×10⁵ cfu/g, respectively. After silo opened, silage was sub-sampled for the analysis of ensiling quality and its rumen fermentation indices. Results: Among the wild type inoculants (CON vs AT vs FD), FD inoculant had higher (p<0.05) in vitro digestibilities of dry matter and neutral detergent fiber, the total degradable fraction, and total volatile fatty acid in rumen, while AT inoculant had higher (p<0.05) lactate, acetate, and lactic acid bacteria in silage. Silage pH and the potentially degradable fraction in rumen increased (p<0.05) by inactivation of antifungal activity (AT vs AT-m), but lactate, acetate, and lactic acid bacteria of silage decreased (p<0.05). In silage, acetate increased (p<0.05) by inactivation of esterase activity (FD vs FD-est) with decreases (p<0.05) of pH, ammonia-N, lactate, and yeast. Moreover, inactivation of esterase activity clearly decreased (p<0.05) in vitro digestibilities of dry matter and neutral detergent fiber, the total degradable fraction, and total volatile fatty acid in the rumen. Conclusion: This study concluded that FD inoculant confirmed esterase activity on rye silage harvested at dough stage, while AT inoculant could not be confirmed with antifungal activity due to the absence of mold in all silages.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.709-714
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• 1997

$TiO_2$ hydrate coating on mica in an aqueous solution of $TiOSO_4$ by the hydrolysis using ammonia water studied with emphasis on coating conditions for a uniform coating. For the uniform coating of $TiO_2$ film on mica surface, it was found that smaller mica particles were coated more uniformly compared to larger particles. It was necessary to suppress the rate of formation of hydrated $TiO_2$ particles in solution, which were deposited on mica and generate irregular coating. It was also necessary to control precipitation yield by varying the reaction temperature to obtain uniform coating. More uniform coating was obtained with higher precipitation yield. A uniform dense film was formed when mica particles of average size of $14.7{\mu}m$ is used for mica slurry solution, of which pH is 2.5, and the factor of acidity of $TiOSO_4$ solution is 291, and the solution was kept at $80^{\circ}C$ for 3 hours. The morphology of $TiO_2$ film formed on mica was little affected by firing at $900^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.26-36
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• 2002

A solid-state reaction of $MoO_3$ with as-synthesized H-SAPO-34 generated paramagnetic Mo(V) species. The dehydration resulted in weak Mo(V) species, and subsequent activation resulted in the formation of Mo(V) species such as $Mo(V)_{5c}$ and $Mo(V)_{6c}$ that are characterized by ESR. The data of ESR and ESEM show the oxomolybdenum species, to be $(MoO_2)^+$ or $(MoO)^{3+}$. The $(MoO_2)^+$ species seems to be more probable. Since H-SAPO-34 has a low framework negative charge, $(MoO)^{3+}$ with a high positive charge can not be easily stabilized. A solution reaction between the solution of silico-molybdic acid and calcined H-SAPO-34 resulted in only $(MoO_2)^+$ species. A rhombic ESR signal is observed on adsorption of $D_2O$, $CD_3OH$, $CH_3Ch_2OD$ and $ND_3$. The Location and coordination structure of Mo(V) species has been determined by three-pulse electron spin-echo modulation data and their simulations. After the adsorption of methanol, ethylene, ammonia, and water for MoH-SAPO-34, three molecules, one molecule, one and one molecule, respectively, are directly coordinated to $(MoO_2)^+)$.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.287-294
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• 2007

Effect of combined use of anti-microbial materials, such as ethanol, mustard and chitosan, on the quality of low salted kochujang was investigated during fermentation at $20^{\circ}C$ for 12 weeks. Viable cells of yeast increased remarkably during fermentation, but increasing ratio was significantly low in ethanol-mustard added kochujang. Activity of ${\beta}-amylase$ was high in anti-microbial material added kochujang, whereas ${\alpha}-amylase$ and protease activities were low in those groups. Water activity decreased during fermentation with being low in the control kochujang prepared with normal-salt without anti-microbial materials. Hunter L-, a- and b-values of kochujang increased during fermentation, and the degree of increase in total color difference $({\Delta}E)$ was low in ethanol added kochujang. Titratable acidity of kochujang was decreased in anti-microbial materials added group at late aging period, and oxidation-reduction potential was low in the control kochujang. Total sugar and reducing sugar contents of kochujang were high in ethanol-mustard added kochujang. Ethanol contents of kochujang increased at late aging period, with high values in ethanol-chitosan added kochujang. Amino nitrogen content increased during middle of fermentation, and ammonia nitrogen content of kochujang decreased in ethanol-mustard-chitosan added group during fermentation. After 12 weeks fermentation, sensory results showed that ethanol or ethanol-mustard added kochujang were the highest in color and flavor with the highest overall acceptability.

• Journal of Aquaculture
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• v.9 no.3
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• pp.239-245
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• 1996

As one of the red tide control method, montmorillonite was used to eliminate the causative organisms in Korea and Japan. We assayed the loess to replace the montmorillonite because it distribute in large quantity and nearby the red tide occurrence in South Coast of Korea. By using the mixture of loess and coal ashes, we examined the decreasing level of nutrients such as ammonia and phosphate, the elimination of causative organisms as a chlorophyll a content, and the harmful effect on aquaculture orgarnisms in cage culture farms. Half of the ammonium and phosphate was adsorbed by the loess particles, but only $25\%$ of ammonium was adsorbed by the coal ashes particles. In water column test, the particles of loess and coal ashes were settled down by $80\%$ in 20 minutes, the red tide organisms was eliminated by $80\%$ after 2 hours in 1,000 ppm of loess suspension, but the organisms were eliminated only $30\%$ by the same concentration of coal ashes. The harmful test of fishes and invertbrates, we observed any other negative effects of test animals than a tint deceleration in yellowtail.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.225-231
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• 2001

This study was conducted to find out the optimal aeration rates for minimizing odor emission and for increasing biological activities during composting of livestock manure in the enclosed bench-scale reactor system. It was treated with the mixture of poultry manure and sawdust controlled the initial water content of 60%, then aerated continuously at four different aeration rates (0.1, 0.2, 0.4 and 0.6 L/min/kg dry-solids). The average emitted concentration of ammonia in 0.6 L/min/kg dry-solids during composting reached the level of 40% in comparison with that of 0.2 L/min/kg dry-solids. In cases of sulfur compounds such as hydrogen sulfide, methylmercaptan and ethylmercaptan, their concentrations decreased with increasing aeration rates and the emission time was shortened. But they didn't detect in the treatment of 0.6 L/min/kg dry-solids. The biological activity for composting showed a trend of increasing as aeration rates increased. The treatment of 0.6 L/min/kg dry-solids gave the highest biological activity and the best compost quality.