• 한국유기농업학회지
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• 제16권3호
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• pp.287-298
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• 2008

우분에 왕겨와 볏짚을 1:1, 1:2, 1:3의 부피비율로 혼합한 먹이조건이 지렁이의 생육, 분립생산량, 체조직으로의 유기물 전환율 및 전환효율을 조사하여, 적정 먹이조건을 추정하였다. 1. 우분+왕겨 혼합구가 우분+볏짚 혼합구보다 지렁이의 증체속도, 증식효율 및 분립생산량이 많았다. 특히 우분+왕겨 1:3 혼합비율이 지렁이 생육에 가장 알맞은 먹이조건이었다(Table 2). 2. 우분+왕겨 혼합 구에서 지렁이 체조직으로의 유기물 전환율과 전환효율이 높았던 것은 먹이 중의 휘발성 고형분과 전탄소함량이 높았기 때문이었다(Table 1, 4). 4. 지렁이 분변토는 약알칼리성이고, 전질소함량, 유효인산함량, CEC 및 치환 성 양이온 함량이 높아서 친환경 농자재로 유용하게 활용될 수 있다고 판단된다(Table 5).

• 한국축산시설환경학회지
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• 제18권2호
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• pp.63-74
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• 2012

사육밀도의 차이가 지렁이의 생육, 체조직으로의 유기물 전환효율 및 분립생산량에 미치는 영향을 조사한 결과를 요약하면 다음과 같다. 1. 공시 한우분의 탄질율은 25.1로, 지렁이 먹이로 적합한 탄질율로 추정되었다. 2. 지렁이 생체중과 먹이 량의 비율이 1:32였던 S-3에서 생체중 증가율과 체조직으로의 유기물 전환효율이 유의하게 높은 값을 나타내었는데, 이 비율을 사육공간으로 나타내면 $56.6cm^3$이었다. S-3에서 사육기간 평균 생체중 증가율과 체조직으로의 유기물 전환효율은 각각 10.63 mg/day와 6.65%를 나타내었다. 3. 지렁이 생체중과 먹이 량의 비율 1:8이었던 S-1에서 사육기간 중 분립비율이 가장 높았지만, 생체중 증가율과 체조직으로 유기물 전환효은 -값을 나타내었다. 이는 개체 간 먹이 경합이 심해진 결과로 추정된다. 4. 사육밀도가 높아짐에 따라 지렁이 분립의 pH, 전 질소함량, 유효인산함량, 양이온치환능력 (CEC) 및 양이온 함량이 유의하게 증가되었다. 특히 유효인산함량, 양이온치환능력 및 양이온함량은 사육기간이 길어짐에 따라 유의하게 증가되었다. 5. 지렁이 분립의 이화학적 특성으로 볼 때, 상토 재 또는 토양개량제로서 유용성이 높다고 판단되었다.

• 한국축산시설환경학회지
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• 제15권3호
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• pp.289-296
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• 2009

The effects of the processing mixture of pig manure and various organic wastes on the growth, cast production of earthworm, and conversion of organic matter to earthworm tissues by vermicomposting. The substances used in this experiments were sawdust, rice hull, coffee waste, brewery waste, litters, turfgrass cutting residues, rice bran, vegetable wastes and rice straw and were mixed with pig manure at a ratios of 50:50 (v/v), and pig manure 100% (control), respectively. The highest values of growth parameters, cast production and conversion efficiency of organic matter to earthworm tissues were obtained at the mixtures of pig manure with coffee waste, it may due to the favourable diet conditions to process with pig manure by vermicomposting. But, all of the earthworm died in the pig manure 100% (control) and pig manure with vegetable wastes treatments by vermicomposting was impossible in this experiment. The vermicast contained a higher values of total nitrogen, available phosphorus, exchangeable cations and cation exchange capacity than their parent materials with increased availability of nutrients and improved physicochemical properties.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.179-189
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• 1997

Among aftertreatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now studied actively. In this study, a transient one-dimensional model developed to simulate the thermal and conversion characteristics of adiabatic monolithic converters operating under warm up conditions is presented. This model takes into account the gas solid heat and mass transfer, axial heat conduction, chemical reactions and the related heat release. The model has been used to analyze the transient response of an axisymmetric catalytic converter during a warm-up as a function of catalyst design parameters and operation conditions in order to observe their effects on the lightoff behaviour. The experimental test was carried out 2400 cc light diesel engine with DOC.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.164-170
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• 1996

Among after treatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects on factors of oxidaton characteristics and conversion efficiency of DOC. We tested to estimate change of engine performance whether a 11,000cc diesel engine equipps with DOC or not. We conducted test to estimate the reduction efficiency of exhaust gas in P-5 mode, in D-13 mode of heavy duty diesel regulation mode and in somoke opacity mode for two samples and also we conducted test to analyze the effects about both exhaust gas velocities 1,100rpm and 2,200rpm

• Asian-Australasian Journal of Animal Sciences
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• 제14권4호
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• pp.474-478
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• 2001

Eighteen Murrah male buffalo calves were allotted into three groups of six each. The calves in group I (control) were fed with whole milk, skim milk, calf starter and green maize fodder. The calves in group II (high butyric acid) and group III (low butyric acid) were fed with the same diet as control along with 24 ml and 12 ml of butyric acid/calf/day for 120 days, respectively for 120 days. Dry matter intake was higher in group II and III as compared with group I. Digestibility of dry matter, organic matter, crude protein, crude fibre, ether extract, neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose was the highest in group II followed by group III and the control group. Body weight gain and conversion efficiency of dry matter, digestible crude protein and total digestible nutrients were better in group II. Cost of feed for per unit of live weight gain was the lowest in group II. It was concluded that dietary addition of butyric acid (24 ml/day) was economical and had positive effect on the performance of Murrah buffalo calves.

• 한국물환경학회지
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• 제35권4호
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• pp.362-369
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• 2019

In this study, biodegradation efficiency improvement of mixed sludge for the anaerobic digestion process in wastewater treatment plant was investigated. In order to release the organic material contained in the sludge cell and promote the hydrolysis step, mixed sludge of 7% TS (Total Solids) was physically shear-treated at a shear strength of 1,000 ~ 4,000 rpm and a maximum of 120 mins. As a result of the comparison between mixed sludge before and after the treatment, the concentration of $SCOD_{Cr}$(Soluble Chemical Oxygen Demand-chromium method) was increased through the conversion of granular organic matter into dissolved organic matter as shear strength and treatment time increases. The solubilization efficiency increased rapidly after 30 min of solubilization application time, and they were 11.23 %, 20.10 %, 22.52 % and 25.43% at 120 min for each shear strength conditions, respectively. Additionally, the BMP(Biochemical Methane Potential) test was conducted with the optimized samples to determine the increase of methane production by the shear pre-treatment. Consequently, methane production of each samples were 0.275, 0.310, 0.323 and $0.335m^3/kg\;VS_{add}$, which indicates that methane production was increased to a maximum of 21.28% compared to the control without the solubilization process ($0.262m^3/kg\;VS_{add}$). As a result, the physical shear-treatment is a promising process for sewage sludge pre-treatment to reduce the organic waste and increase the energy production.

• 한국환경농학회지
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• 제35권2호
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• pp.128-136
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• 2016

BACKGROUND: Hydrothermal carbonization reaction is the thermo-chemical energy conversion technology for producing the solid fuel of high carbon density from organic wastes. The hydrothermal carbonization reaction is accompanied by the thermal hydrolysis reaction which converse particulate organic matters to soluble forms (hydro-thermal hydrolysate). Recently, hydrothermal carbonization is adopted as a pre-treatment technology to improve anaerobic digestion efficiency. This research was carried out to assess the effects of hydro-thermal reaction temperature on the methane potential and anaerobic biodegradability in the thermal hydrolysate of organic sludge generating from the wastewater treatment plant of poultry slaughterhouse .METHODS AND RESULTS: Wastewater treatment sludge cake of poultry slaughterhouse was treated in the different hydro-thermal reaction temperature of 170, 180, 190, 200, and 220℃. Theoretical and experimental methane potential for each hydro-thermal hydrolysate were measured. Then, the organic substance fractions of hydro-thermal hydrolysate were characterized by the optimization of the parallel first order kinetics model. The increase of hydro-thermal reaction temperature from 170℃ to 220℃ caused the enhancement of hydrolysis efficiency. And the methane potential showed the maximum value of 0.381 Nm³ kg^-1-VS_added in the hydro-thermal reaction temperature of 190℃. Biodegradable volatile solid(VSB) content have accounted for 66.41% in 170℃, 72.70% in 180℃, 79.78% in 190℃, 67.05% in 200℃, and 70.31% in 220℃, respectively. The persistent VS content increased with hydro-thermal reaction temperature, which occupied 0.18% for 170℃, 2.96% for 180℃, 6.32% for 190℃, 17.52% for 200℃, and 20.55% for 220℃.CONCLUSION: Biodegradable volatile solid showed the highest amount in the hydro-thermal reaction temperature of 190℃, and then, the optimum hydro-thermal reaction temperature for organic sludge was assessed as 190℃ in the aspect of the methane production. The rise of hydro-thermal reaction temperature caused increase of persistent organic matter content.

• 한국환경보건학회지
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• 제37권4호
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• pp.315-322
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• 2011

Objectives: Organic matter and nitrogen were removed using the EGSB process, a high-rate anaerobic process, in combination with a nitritation-denitritation process, in order to ensure the stable treatment of seafood processing wastewater. Methods: The upflow velocity of an EGGS reactor was operated at 10 m/hr for maximal organics removal efficiency. For removal of nitrogen from seafood processing wastewater a nitritation-denitriation process was applied Results: The efficiency of the EGSB process showed that it has an 80% or more organic matter (CODcr) removal efficiency with an HRT of six hours or more at influent loadings of 17.34 kgCOD/$m^3$/day or less. The methane product for TCODcr removal was 0.23-0.38 $m^3CH_4$/kgCODrem., which was similar to the theoretical generation of STP-state methane, 0.35 $m^3CH_4$/kgTCODrem. In the nitritation-denitritation process, the nitritation conversion rate to $NH_4^+$-N concentration was 82% to 87%, 72% to 81% and 64% to 69% when HRT was 24 hr, 21 hr and 18 hr, respectively. In the denitritation process, the ratio of SCOD consumption to NOx-N removal ranged from 2.347 to 2.587. It was 2.472 on average. Conclusions: The optimal HRT for stable processing of seafood processing wastewater is six hours or more. The ratio of nitrite to total NOx-N was 82% to 96%, which indicates that nitrite accounts for the largest portion of the product.

• ETRI Journal
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• 제35권4호
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• pp.587-593
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• 2013

We demonstrate semitransparent organic photovoltaics (OPVs) based on thin metal electrodes and polymer photoactive layers consisting of poly(3-hexylthiophene) and [6,6]-phenyl $C_{61}$ butyric acid methyl ester. The power conversion efficiency of a semitransparent OPV device comprising a 15-nm silver (Ag) rear electrode is 1.98% under AM 1.5-G illumination through the indium-tin-oxide side of the front anode at 100 $mW/cm^2$ with 15.6% average transmittance of the entire cell in the visible wavelength range. As its thickness increases, a thin Ag electrode mainly influences the enhancement of the short circuit current density and fill factor. Its relatively low absorption intensity makes a Ag thin film a viable option for semitransparent electrodes compatible with organic layers.