• Clean Technology
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• v.29 no.2
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• pp.126-134
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• 2023

Direct catalytic decomposition is a promising method for controlling the emission of nitrous oxide (N₂O) from the semiconductor and display industries. In this study, a γ-Al₂O₃ catalyst was developed to reduce N₂O emissions by a catalytic decomposition reaction. The γ-Al₂O₃ catalyst was prepared by an extrusion method using boehmite powder, and a N₂O decomposition test was performed using a catalyst reactor that was approximately 25.4 mm (1 in) in diameter packed with approximately 5 mm of catalysts. The N₂O decomposition tests were carried out with approximately 1% N₂O at 550 to 750 ℃, an ambient pressure, and a GHSV=1800-2000 h^-1. To confirm the N₂O decomposition properties and the effect of O₂ and steam on the N₂O decomposition, nitrogen, air, and air and steam were used as atmospheric gases. The catalytic decomposition tests showed that the 1% N₂O had almost completely disappeared at 700 ℃ in an N₂ atmosphere. However, air and steam decreased the conversion rate drastically. The long term stability test carried out under an N₂ atmosphere at 700 ℃ for 350 h showed that the N₂O conversion rate remained very stable, confirming no catalytic activity changes. From the results of the N₂O decomposition tests and long-term stability test, it is expected that the prepared γ-Al₂O₃ catalyst can be used to reduce N₂O emissions from several industries including the semiconductor, display, and nitric acid manufacturing industry.

• Journal of Animal Science and Technology
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• v.46 no.1
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• pp.61-68
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• 2004

An experiment was conducted to evaluate condensed molasses solubles(CMS, a by-product from monosodium glutamate production) as a source of nitrogen for ruminant with particular reference to its effects on microbial protein synthesis. Four non-lactating dairy cows fitted with rumen cannulas were used in a 4 ${\times}$ 4 Latin square with 14-day periods. The four treatments were (1) basal diet consisting of barley straw ad libitum and 3 kg/d of rolled barley, (2) basal diet plus 200 gld molasses and 300 g/d water, (3) basal diet plus 200 g/d molasses, 100 g/d CMS and 200 g/d water, (4) basal diet plus 200 g/d molasses, 200 g/d CMS and 100 g/d water. Ruminal pH remained at high levels and showed little variation during the day between treatments. The concentration of total and individual VFA in the rumen was similar between treatments. There was no difference in the concentration of ammonia in the rumen between treatments, although the intake of nitrogen in molassesl CMS mixture treatments was higher than that of control and molasses treatment. But there was a suggestion of an increased synthesis of microbial protein with the higher level of inclusion of CMS when the allantoin/creatinine ratio was used as an index of microbial protein production(P <0.10).

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.3
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• pp.199-206
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• 1982

A field experiment was conducted to compare the effects of compost and rice straw application on the growth of soybean, chemical properties and soil microorganism in newly reclaimed silty clay loamy upland soil. Application rates of the arganic materials were 750 Kg, 1,500 Kg and 3,000 Kg/10a in compost, and 340 Kg, 680 Kg and 1,360 Kg/10a in rice straw. The differences of N.P.K. application rates caused by the two different organic materials were balanced by chemical fertilizers of N.P.K. The results can be summarized as follows; 1. The yield of soybean was increased upon compost application, but no significant difference on yield was observed except luxuriant plant growth upon rice straw application. 2. There was highly possitive correlation between concentration of phosphorous, potassium in soybean plant at 71 days after planting and dry weight of grain vs. stem plus bean chaff of harvest plant in compost applied plots, but no correlation was found in rice straw applied plots. 3. In greneral, the soil water contents in organic material applied plots, expecially in plots of rice straw, were higher than in no organic material plots. However, at wilting point, the soil water content in organic material applied plot was lower compare to no organic material plot. 4. The weight of nodules per soybean plant was heavier notwithstanding the fewer number of soil bacteria and fungi in compost application plots than rice straw application plots.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.304-310
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• 2003

Effects of different amounts of fertilizer and manure application on changes of chemical and biological properties of soil were studied in plastic film house. Application amount of fertilizer was determined on the basis of soil test, standard application rate, and conventional rate of farmers. Lettuce in the first and second seasons and spinach in the third season were cultivated. Crop yields were highest in the plot fertilized on the basis of soil test during the three crop seasons. In the third crop season, spinach yield was lower in conventional plot applied with larger amount of pig manure compost than any other treatment. Organic matter, available phosphorus, and exchangeable potassium were accumulated in soil of the conventional plot with successive cropping. There was no difference in the abundance of soil invertebrates among the treatments, but soil enzyme activity was highest in the conventional plot.

• Journal of Animal Science and Technology
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• v.51 no.1
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• pp.45-52
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• 2009

This experiment was conducted to observe the effects of anaerobic cellulolytic bacteria culture (Ruminococcus flavefaciens H-20 and Fibrobactor succinogenes H-23) on in vivo ruminal fermentation characteristics in Hanwoo heifers. Four ruminally cannulated Hanwoo heifers ($221\pm7.5kg$) receiving a basal diet containing 3 kg of mixture hay (tall fescue and ochardgrass) and 2 kg of concentrate per day were in a $4\times4$ Latin square with 21-day periods. Treatments were the basal diet without the culture additive (control), the basal diet plus 50 ml/day of bacteria culture of H-20 and H-23 (1%), 150 ml/day of H-20 and H-23 (3%), and 250 ml/day of H-20 and H-23 (5%). In the whole experimental periods, ruminal pH did not differ between treatments. However, the concentration of ruminal ammonia-N was increased in the 3% treatment relative to control and the 1% treatment at 1 hr post-feeding (p<0.05). Avicelase and CMCase (carboxymethyl cellulase) activities in rumen fluid showed no significant difference among treatments. However, xylanase activity was higher in the 5% (119.49, xylose ${\mu}mol$/ml/min) than the 3% treatment (71.02, xylose ${\mu}mol$/ml/min) at 0 hr post-feeding (p<0.05). Concentrations of ruminal total VFA, acetate, propionate and valerate were unaffected by treatments, while butyrate was higher in the 3% treatment (24.48 mM) than control (15.71 mM) at 1 hr post-feeding (p<0.05). Results indicate that minimum 3% inclusion of cellulolytic bacteria cultures improved ruminal fermentation, especially ammonia-N concentration and butyric acid production.

• Composites Research
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• v.14 no.3
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• pp.18-31
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• 2001

Interfacial and microfailure properties of the modified steel, carbon and glass fibers/cement composites were investigated using electro-pullout test under tensile and compressive tests with acoustic emission (AE). The hand-sanded steel composite exhibited higher interfacial shear strength (IFSS) than the untreated and even neoalkoxy zirconate (Zr) treated steel fiber composites. This might be due to the enhanced mechanical interlocking, compared to possible hydrogen or covalent bonds. During curing process, the contact resistivity decreased rapidly at the initial stage and then showed a level-off. Comparing to the untreated case, the contact resistivity of either Zr-treated or hand-sanded steel fiber composites increased to the infinity at latter stage. The number of AE signals of hand-sanded steel fiber composite was much more than those of the untreated and Zr-treated cases due to many interlayer failure signals. AE waveforms for pullout and frictional signals of the hand-sanded composite are larger than those of the untreated case. For dual matrix composite (DMC), AE energy and waveform under compressive loading were much higher and larger than those under tensile loading, due to brittle but well-enduring ceramic nature against compressive stress. Vertical multicrack exhibits fur glass fiber composite under tensile test, whereas buckling failure appeared under compressive loading. Electro-micromechanical technique with AE can be used as an efficient nondestructive (NDT) method to evaluate the interfacial and microfailure mechanisms for conductive fibers/brittle and nontransparent cement composites.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.561-572
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• 2008

Responses of real-time control parameters, such as ORP, DO and pH, to the conditions of biological animal wastewater treatment process were examined to evaluate the stability of real-time control using each parameter. Also an optimum index for supplemental carbon source addition based on NOx-N level was determined under a consideration of denitrification rate by endogenous respiration of microorganism and residual organic matter in liquor. Experiment was performed with lab-scale sequencing batch reactor(SBR) and working volume of the process was 45L. The distinctive nitrogen break point(NBP) on ORP-and DO-time profiles, which mean the termination of nitrification, started disappearing with the maintenance of low NH4-N loading rate. Also the NBP on ORP-and DO-time profiles was no longer observed when high NOx-N was loaded into the reactor, and the sensitivity of ORP became dull with the increase of NOx-N level. However, the distinctive NBP was constantly occurred on pH(mV)-time profile, maintaining unique profile patterns. This stable occurrence of NBP on pH(mV)-time profile was lasted even at very high NOx-N:NH4-N ratio(over 80:1) in reactor, and the specific point could be easily detected by tracking moving slope change(MSC) of the curve. Revelation of NBP on pH(mV)-time profile and recognition of the realtime control point using MSC were stable at a condition of over 300mg/L NOx-N level in reactor. The occurrence of distinctive NBP was persistent on pH(mV)-time profile even at a level of 10,000mg/L STOC(soluble total organic carbon) and the recognition of NBP was feasible by tracing MSC, but that point on ORP and DO-time profiles began to disappear with the increase of STOC level in reactor. The denitrfication rate by endogenous respiration and residual organic matter was about 0.4mg/L.hr., and it was found that 0.83 would be accepted as an index for supplemental carbon source addition when 0.1 of safety factor was applied.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.227-234
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• 2017

This study aimed to investigate the nutrient solution developed by based on nutrient-water absorption rate of strawberry 'Maehyang' by comparing growth and yield for 8 months with 5 kinds of nutrient solution with different ion composition. Strawberry plants were planted at elevated bed and supplied with five kinds of nutrient solutions (RDA), Yamazaki, PBG, University of Seoul (UOS) and NewUOS from one month onwards. Five types of nutrient solution were supplied to the strawberry plants associated with EC $1.0dS{\cdot}m^{-1}$, pH 6.0, $150{\sim}300mL{\cdot}plant^{-1}$ per day. At 60 days after planting, leaf width and leaf petiole of the strawberry plants showed significant differences among nutrient solution types and photosynthesis was higher in RDA and NewUOS nutrient solution and lower in PBG nutrient solution. The EC of the drainage on vegetative growth stage was $0.7{\sim}0.8dS{\cdot}m^{-1}$, which is lower than the supplied EC level, and to $1.0-1.2dS{\cdot}m^{-1}$, afterwards. The pH of the drainage was higher in Yamzaki solution as 6.2~6.8, while the pH of the UOS nutrient solution was lower in 5.1~5.2. Nitrate content was most absorbed in vegetative growth stage and after flower clusters development. The potassium uptake was highest at the NewUOS followed by UOS and Yamazaki nutrient solution. At six months after -planting fresh weight and dry weight of shoot and root were higher in UOS and NewUOS nutrient solution than other nutrient solutions, and the dry matter ratio was lower at 43.5% in Yamazaki nutrient solution and 30.6% in NewUOS nutrient solution than other solutions. Length, width, weight, and sugar content of the strawberries harvested from December to February were unaffected by treatment, but yield was higher in NewUOS nutrient solution due to increasing fruit number and average weight. From March to May, number of fruit was higher in Yamazaki nutrient solution. In conclusion, there was no difference in the growth of 'Maehyang' when 5 nutrient solutions were grown under hydroponics. But in order to improve the marketability, the NewUOS nutrient solution is appropriate to use from planting to February and it is suitable to use Yamazaki nutrient solution after March when temperature is high and the amount of fruit set per inflorescence.

• Korean Journal of Organic Agriculture
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• v.16 no.2
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• pp.219-230
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• 2008

This trial was conducted to assess effects of cattle slurry application on productivity and feed values of barley and hairy vetch when they were influenced by single or mixed-sowed cultivation in paddy fields, and to obtain good quality of organic forage resources. The results summarized are as follows. For barley and hairy vetch, single-sowed cultivation was lower in annual dry matter (DM) and total digestible nutrients (TDN) yields than mixed-sowed (P<0.05). Although crude protein (CP) contents for the barley within single-sowed treatments were lowest as 6.5%, those of hairy vetch within the same sowed method were highest as 16.7%. However, mixed-sowed cultivation with barley and hairy vetch, showing 13.8% CP content, was significantly (P<0.05) higher than CP and relative feed value (RFV) of barley alone treatment. For barley alone treatment, cattle slurry application significantly increased annual DM and TDN yields in comparison with treatments of P+K fertilization as chemical fertilizers and no fertilizer as controls. Results from cattle slurry application showed 84% and 82% in contrast with chemical fertilizer for annual DM and TDN yields, respectively. For mixed-sowed cultivation with barley and hairy vetch, cattle slurry application showed 90% and 94% annual DM and TDN yields, respectively as compared with N+P+K fertilization as chemical fertilizers. Crude protein contents ($14.2{\sim}15.9%$) for cattle slurry application treatments were significantly (P<0.05) higher than those of other treatments. Moreover, cattle slurry application treatment had the highest TDN and RFV among treatments, showing $60.7{\sim}61.8%$ and $112.2{\sim}118.1$, respectively. For hairy vetch alone treatments, annual DM and TDN yields of cattle slurry alone application treatment were highest among fertilization treatments. Furthermore, CP, TDN and RFV of cattle slurry alone application treatments were significantly (P<0.05) higher than those of other treatments. The results showed that mixed-sowed cultivation rather than single-sowed for barley or hairy vetch improved their nutritive value and quality, and also within mixed-sowed cultivation, cattle slurry application increased production yield per ha and CP contents. In the application of above system to organic livestock farming, it would be expected that forages produced by cattle slurry application under mixed-sowed method might become a substitute for foreign organic grain as protein sources.

• Journal of Applied Biological Chemistry
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• v.56 no.4
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• pp.229-234
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• 2013

Coal ash can be added to agricultural soils to increase the chemical properties of soil such as pH, cation exchange capacity and nutrient availability of - B, Ca, Mo etc-. Therefore, the main purpose of this study was to evaluate the feasibility of fly ash as a soil amendment in paddy soils. Selected fly ash was mixed with bentonite and calcium hydroxide at the ratio of 80:15:5 (w/w) and manufactured as a pellet type at the size of 10 mm. Field experiments were conducted to evaluate the effects of fly ash fertilizer on the soil quality and crop growth compare to the control (no fertilizer) and, - traditional fertilizer. Results showed that soil pH and organic matter in paddy soils after applying the manufactured fly ash fertilizer were not increased compared to the other two treatments. However, the concentration of available phosphate and silicate in paddy soils were higher than those of the control and traditional fertilization. With regard to crop growth, no significant difference was observed between three different treatments. However, the content of protein in the rice grain cultivated with the fly ash fertilizer was higher than in the rice cultivated by other two treatments. Overall, fly ash fertilizer could increase the concentration of available silicate and phosphate in the paddy soil and improve the rice quality. In conclusion, fly ash can be utilized in agricultural soils as soil amendment, especially in the rice paddy soil.