• 대한환경공학회지
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• 제31권5호
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• pp.341-345
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• 2009

음식물쓰레기와 종이류로 구성된 유기성고형폐기물(고형물 함량 30% TS)을 대상으로 중온 건식혐기성소화를 시도하였고, 연속 운전 중 수리학적 체류 시간(HRT)을 150일, 100일, 60일, 40일로 감소시켰다. 기질의 고형물 농도를 30% TS (Total Solids)로 고정하였기 때문에 각각의 HRT에 해당하는 고형물 부하는 2.0, 3.0, 5.0, 7.5 kg TS/$m^3$/d였다. HRT를 줄임에 따라 단위용적 당 바이오가스 생산 속도는 증가하였고, HRT 40일에서 3.49${\pm}$0.31 $m^3/m^3/d$로 가장 높은 성능을 보였다. 이 때, 76%의 휘발성 고형물(VS) 분해율이 유지되었고, 0.25 $m^3$/kg $TS_{added}$의 메탄 생산 전환율을 보였으며, 이는 기질의 67.4%에 해당하는 에너지가 메탄 가스로 전환된 것을 의미한다. HRT 100일에서 0.52 $m^3$/kg $TS_{added}$로 가장 높은 바이오가스 전환율을 보였지만, 모든 HRT에서 0.45${\sim}$0.52 $m^3$/kg $TS_{added}$로 큰 차이가 나지 않았다. 고형물 함량이 높은 기질의 원활한 주입을 위해 소화조 발효액의 일부를 기질 투입구로 반송하여 기질과 혼합 후 주입하였다. 주입하고자 하는 기질의 5배에 해당하는 양의 소화조 발효액을 반송하여 혼합하였을 때, 가장 효과적인 기질 주입이 이루어졌다. 중온 건식 조건에서 서식하는 메탄 소화균의 활성도를 측정한 결과, 아세트산, 뷰틸산, 프로피온산을 이용할 경우 각각 2.66, 1.94, 1.20 mL $CH_4/g$ VS/d였다.

• Asian-Australasian Journal of Animal Sciences
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• 제4권3호
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• pp.235-240
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• 1991

A CRD experiment with thirty growing cross bred calves were assigned at random to three treatments rations. 1) $T_0$, 0% Urea + 20% M. O. cake, 2) $T_1$, 1% Urea + 10% M. O. cake and 3) $T_2$, 2% Urea + 0% M. O. cake to develop a rice straw based ration for ruminants. Sweetish odour and yellowish colour were observed in good recovered silage. Organic matter varied from 87.45% to 89.63% whereas crude protein varied from 14.0% to 14.5% in each treatment. No significant differences were found among the nutrient composition of the ration. The dry matter in take (DMI) and dry matter digestibility was higher in $T_0$ (0% Urea) than those of ration containing 1% ($T_1$) and 2% Urea ($T_2$). The organic matter digestibility decreases with increasing doses of urea. The crude protein & nitrogen-free-extract digestibility were found higher in the ration $T_1$ containing 1% urea whereas crude fibre digestibility and available metabolizable energy (ME) were higher in $T_0$ containing no urea as compared to $T_1$ and $T_2$. Total digestible nutrient (TDN) decreases with the increase of urea level. The highest feed efficiency was found in $T_0$ having no urea and lowest was in $T_2$. The animals gained in weights from each ration. Highest gain in weight was found in $T_0$ ration, then followed $T_1$, and $T_2$. This is due to natural protein available in M. O. cake only. It is concluded that supplemetation of urea or M. O. cake with readily available energy source as molasses upto 20% of total dietary dry matter in a complete ration may increase the intake of low quality fibrous roughage only when nitrogen and mineral are not limiting factor.

• Asian-Australasian Journal of Animal Sciences
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• 제5권3호
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• pp.465-468
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• 1992

Urinary purine derivatives and creatinine excretion was measured in a total of 4 white Alpine sheep. They were given diets 718 to 1060 g/kg dry matter (DM) of roughage. The crude protein content of this diets was on average $93.87{\pm}5.57g$ in kg DM. Purine derivatives-N excretion increased linearly with incremental DM intake and was significantly correlated (n = 16) with amounts of digestible organic matter (DOM) intake: allantoin-N (mg) = 1.205 (${\pm}0.070$) $\times$ DOM (g) - 136.709 (${\pm}37.399$), r = 0.9770, RSD = 22.97; uricacid-N (mg) = 0.131 (${\pm}0.041$) $\times$ DOM (g) + 11.380 (${\pm}21.881$), r = 0.6306, RSD = 13.44; Hypoxanthine-N (mg) = 0.049 (${\pm}0.014$) $\times$ DOM (g) - 28.640 (${\pm}7.708$), r = 0.6544, RSD = 4.73; total purine derivatives-N (mg) = 1.385 (${\pm}0.083$) $\times$ DOM (g) - 90.261 (${\pm}44.552$), r = 0.9706, RSD = 27.47. Microbial protein synthesis per kg DOM was estimated of 113 g. The urinary creatinine-N excretion was on average 9.10 mg/kg live weight (LW) with a standard error of 0.12 mg creatinine-N per kg LW. The excretion of creatinine excreton was not related to feed intake. Daily creatinine excretion (mg/d) was calculated from individual LW measurements and the average creatinine excretion (mg/kg LW). It was possible to predict the daily urinary purine derivatives excretion (r = 0.9720 for allantoin, r = 0.9886 for total purine derivatives) from the ratio of purine derivatives (mg/100 ml) and creatinine (mg/100 ml) in the urine and the daily creatinine excretion.

• Environmental Engineering Research
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• 제20권3호
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• pp.223-229
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• 2015

The application of coagulation for feed water pretreatment prior to microfiltration (MF) process has been widely adopted to alleviate fouling due to particles and organic matters in feed water. However, the efficiency of coagulation pretreatment for MF is sensitive to its operation conditions such as pH and coagulant dose. Moreover, the optimum coagulation condition for MF process is different from that for rapid sand filtration in conventional drinking water treatment. In this study, the use of response surface methodology (RSM) was attempted to determine coagulation conditions optimized for pretreatment of MF. The center-united experimental design was used to quantify the effects of coagulant dose and pH on the control of fouling control as well as the removal organic matters. A MF membrane (SDI Samsung, Korea) made of polyvinylidene fluoride (PVDF) was used for the filtration experiments. Poly aluminum chloride (PAC) was used as the coagulant and a series of jar tests were conducted under various conditions. The flux was $90L/m^2-h$ and the fouling rate were calculated in each condition. As a result of this study, an empirical model was derived to explore the optimized conditions for coagulant dose and pH for minimization of the fouling rate. This model also allowed the prediction of the efficiency of the coagulation efficiency. The experimental results were in good agreement with the predictions, suggesting that RSM has potential as a practical method for modeling the coagulation pretreatment for MF.

• 유기물자원화
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• 제9권4호
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• pp.99-104
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• 2001

곱게 갈아 액화시킨 음식물 찌꺼기를 기질로 생균사료를 생산하기 위한 효모의 호기적 액상발효에 있어서 효모증식에 대한 교반속도의 영향을 연구하였다. screening을 통해 선택한 효모인 Kluyvermyces marxianus를 종균으로 2liter jar fermenter를 이용하여 호기적 조건에서 곱게 분쇄해 10% 고형분 함량을 갖는 기질에 교반속도를 500rpm, 900rpm, 1200rpm를 다르게 조정하여 $35^{\circ}C$에서 증식시켰다. 효모의 증식을 촉진시키기 위하여 고분자물질을 분해하는 효소를 분비하는 곰팡이 Aspergillus oryzae와 혼합발효를 실시하여 단독발효와 비교하였다. 발효결과 교반속도가 증가할수록 생균수도 높아져 400rpm에서보다는 900rpm에서 높은 생균수를 보였으나 1200rpm에서는 오히려 감소하였다. 혼합발효는 amylase의 역가를 높여주어 증식속도를 높여 주나 발효종료단계에서 최고 생균수를 증가시켜주지는 않는 것으로 나타났다.

• 유기물자원화
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• 제10권3호
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• pp.126-131
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• 2002

남은 음식물을 기질로 생균사료를 생산하기위하여 고온성 세균에 의한 호기적 액체 발효가 시도되었다. 토양이나 남은 음식물들로부터 11종의 고온성 세균이 $55^{\circ}C$에서의 진탕배양에 의해 분리되었다. 이들 분리균 들의 기질분해능을 평가하기위해 배양액 중에서의 ${\alpha}-amylase$ 와 protease효소역가를 측정 비교하였다. 이 결과 6종의 세균이 선택되었고 남은 음식물 기질 적응력을 높이기 위해 반복 배양을 실시하였다. 발효말기에서의 생균농도는 대부분 $3{\sim}7{\times}10^9/ml$에 이르렀다. 이들 중 B3, B6가 가장 높은 효소역가를 나타냈다. B3, B6, 그리고 분양받은 균주인 Bacillus Stearothermophillus를 2L-jar fermenter를 이용해 혼합발효시킨 결과발효개시 8시간 내에 생균수가 $1.4{\times}10^{10}/ml$에 이르렀다.

• 한국유기농업학회지
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• 제20권3호
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• pp.327-343
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• 2012

In order to develop a high cellulolytic direct-fed microorganism (DFM) for ruminant productivity improvement, this study isolated cellulolytic bacteria from the rumen of Holstein dairy cows, and compared their cellulolytic abilities via DM degradability, gas production and cellulolytic enzyme activities. Twenty six bacteria were isolated from colonies grown in Dehority's artificial (DA) medium with 2% agar and cultured in DA medium containing filter paper at $39^{\circ}C$ for 24h. 16s rDNA gene sequencing of four strains from isolated bacteria showed that H8, H20 and H25 strains identified as Ruminococcus flavefaciens, and H23 strain identified as Fibrobacter succinogenes. H20 strain had higher degradability of filter paper compared with others during the incubation. H8 (R. flavefaciens), H20 (R. flavefaciens), H23 (F. succinogenes), H25 (R. flavefaciens) and RF (R. flavefaciens sijpesteijn, ATCC 19208) were cultured in DA medium with filter paper as a single carbon source for 0, 1, 2, 3, 4 and 6 days without shaking at $39^{\circ}C$, respectively. Dry matter degradability rates of H20, H23 and H25 were relatively higher than those of H8 and RF since 2 d incubation. The cumulative gas production of isolated cellulolytic bacteria increased with incubation time. At every incubation time, the gas production was highest in H20 strain. The activities of carboxymethylcellulase (CMCase) and Avicelase in the culture supernatant were significantly higher in H20 strain compared with others at every incubation time (p<0.05). Therefore, although further researches are required, the present results suggest that H20 strain could be a candidate of DFM in animal feed due to high cellulolytic ability.

• 멤브레인
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• 제15권1호
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• pp.44-51
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• 2005

유기증기에 대한 PDMS의 단점을 보완하기 위해 4,4'-diphenylmethane diisocyanate (MDI)와 1,4-butanediol(BD)를 이용하여 poly(dimethylsiloxane)를 기초로 한 polyurethane-polysiloxanes (PU/PDMS)를 합성하였다. 그리고 poly(tetrafluoroethylene) (PTFE)를 다공성 지지체로 이용하여 복합막을 제조하여 SEM 분석으로 코팅층의 존재와 두께를 확인하였다. 증기투과실험에서 투과온도와 feed의 농도가 증가할수록 flux는 점차 증가하였고, separation factor는 이와 반대로 점차 감소하는 'trade-off'현상을 보였다. 본 연구에서의 PU/PDMS는 soft segment의 함량보다는 비교적 hard segment의 함량이 높기 때문에 투과온도의 증가에 따른 영향이 크지 않았던 것으로 사료된다. PU/PDMS막은 VOCs와 상대적으로 높은 친화도를 가지고 있기 때문에 PU/PDMS 균질막과 비교하여 복합막의 형태에서도 향상된 flux와 높은 separation factor를 나타내었다.

• 한국유기농업학회지
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• 제12권4호
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• pp.411-425
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• 2004

The aim of this experiment was to investigate the effects of applying times and dilution rates of cattle slurry with water on dry matter yields and feed values of orchard grass. Cattle slurry was applied at the rates of average nitrogen fertilizer equivalent to 150kg/ha/year in 3 cutting frequency. Significantly higher dry matter yields than that of no fertilization (7.36 ton DM/ha) were recorded in the application of diluted cattle slurry (10.74~13.54 ton DM/ha) (p<0.05). Especially, this tendency was shown with higher annual dry matter yields at the partitioned dressing times, such as at the applications for 1st and 3rd growth, 2nd and 3rd growth, and 1st, 2nd and 3rd growth respectively. The yields of annual dry matter at fertilizing phosphorus, potassium and nitrogen were higher than no fertilization as 12.42 tons per ha. However, with application of diluted cattle slurry, dry matter yields per year (11.96 ton DM/ha) were significantly higher than those of fertilizing phosphorus and potassium (7.52 ton DM/ha) (p<0.05). The efficiencies of dry matter production with mineral and cattle slurry nitrogen application (kg DM/kg N) were 32.7 and 13.4~26.9kg DM/kg N respectively. Especially, these tendencies were higher in diluted application plots than in no-diluted application plots of cattle slurry. The contents of crude protein (CP, %), neutral detergent Eber (NDF, %), acid detergent fiber (ADF, %), annual yields of CP (kg/ha) and total digestible nutrient (TDNY, kg/ha) of orchardgrass were significantly higher at the application of diluted cattle Slurry than those at non-fertilizer application (p<0.05).

• Fisheries and Aquatic Sciences
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• 제21권11호
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• pp.32.1-32.7
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• 2018

Trout production is a growing activity in recent years but requires new alternative sources of feed to be sustainable over time. The objective of this research was to determine the apparent digestibility coefficient (ADC) of dry matter (DM), organic matter (OM), crude protein (CP) and digestible energy (DE) of $ka{\tilde{n}}iwa$ (Chenopodium pallidicaule Aellen), kiwicha (Amaranthus caudatus L), quinoa (Chenopodium quinoa Willd), beans (Phaseolus vulgaris L.), sacha inchi, (Plukenetia volubilis L) and jumbo squid (Dosidicus gigas) meal in juvenile rainbow trout. The experimental diets were composed of a 70% basal diet and 30% of any raw materials. The ADC was determined by the indirect method using insoluble ash as a non-digestible marker. Jumbo squid, sacha inchi and quinoa showed the highest values of ADC (%) of DM (84.5, 73.5 and 69.7), OM (89.1, 78.4 and 72.9), CP (93.2, 98.0 and 90.3), and DE (4.57, 4.15 and 2.95 Mcal/kg DM), respectively. The ADC values for $ka{\tilde{n}}iwa$, kiwicha and bean were significantly lower. In conclusion, quinoa meal and jumbo squid meal have an acceptable digestibility but sacha inchi meal is a potential alternative for rainbow trout feeding in the future.