• 한국토양비료학회지
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• 제48권5호
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• pp.542-548
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• 2015

This study investigated methane productions and a degradation rate of organic matters by German standard method, VDI4630 test. In this study, 4 livestock byproducts from livestock farm were selected for the investigation. The objective of this study was to estimate a distribution of organic matters by using the double first-order kinetics model in order to calculate the rate of biodegradable organic matters which degrade rapidly in the initial stage and the persistently biodegradable organic matters which degrade slowly later. As a result, all the byproducts applied in this study showed rapid decomposition in the initial stage. Then the decomposition rate began to slow down for a certain period and the rate became 5 times slower than the initial decomposition rate. This trend of decomposition rate changes is typical conditions of organic matter decompositions. The easily degradable factors ($k_1$) ranged between $0.145{\sim}0.257day^{-1}$ and persistent degradable factors ($k_2$) were $0.027{\sim}0.080day^{-1}$. Among these results, greater organic matter decomposition rates from VDI4630 had greater $k_1$ values (0.257, $0.211day^{-1}$) and smaller $k_2$ values (0.027, $0.030day^{-1}$) for dairy wastewater and forage byproduct, respectively.

• 농업과학연구
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• 제48권1호
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• pp.73-81
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• 2021

The current study investigated how Saccharomyces cerevisiae ameliorates the adverse effects of aflatoxin on in vitro rumen fermentation. In this study, five groups (T₁: Control [basal feed]; T₂: T₁ + 300 ppb aflatoxin B1 [AFB₁] and T₃, T₄, and T₅: T₂ with 0.05, 0.1, and 0.2% of S. cerevisiae, respectively) were prepared and incubated in vitro. The results revealed that truly degradable dry matter (TDDM), gas production (GP), microbial biomass production (MBP), truly degradable organic matter (TDOM), partitioning factor (PF), total volatile fatty acids (TVFA), acetate (A), propionate (P) and butyrate (B) values in the control group (T₁) were higher (p < 0.05) than those of the AFB₁ fed group (T₂). The A : P ratio in the control group (T₁) was reduced (p < 0.05) when compared to that of the T₂ group. The TDDM, TDOM, GP, TVFA, A, P, and B values of T₃, T₄, and T₅ improved with the increasing levels of S. cerevisiae; however, the values of group T₅ were lower (p < 0.05) than that of the control. The values of MBP, A : P ratio and PF in group T₅ were statistically similar to that of the control. It was concluded that the inclusion of S. cerevisiae (0.05 to 0.20%) to the AFB₁ (300 ppb) contaminated feed partially to completely ameliorated the adverse effects of AFB₁ on the in vitro rumen fermentation parameters.

• 농업과학연구
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• 제23권2호
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• pp.188-205
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• 1996

본(本) 연구(硏究)는 에너지와 단백질(蛋白質) 공급원(供給源)에 따른 반추위내(反芻胃內) 영양소(營養素) 이용성(利用性) 및 반추위(反芻胃) 미생물(微生物)과의 관계(關係)를 조사하고자 에너지원중 반추위에서 느리게 분해되는 옥수수와 빠르게 분해되는 보리와 beet pulp를 사용하고 단백질원중 빠르게 분해되는 채종박과 느리게 분해되는 옥수수 글루텐과 면실박을 이용 하고, $2{\times}2$요인 시험으로 설계하여 처리당 면양4두를 공시하여 소화율, 반추위 성상 및 미생물 수를 조사한 바 다음과 같이 요약되는 결과를 얻었다. 1. 반추위내(反芻胃內) pH는 사료급여후(飼料給與後) 경과시간에 관계없이 F-F구가 가장 높았고, F-S구가 가장 낮았다 2. 반추위내(反芻胃內) 암모니아 농도는 S-F구가 다른 처리구보다 높았으며, 모든 처리구에서 사료급여 직후 급격히 증가하여 1시간째 최고에 달하였다가 이후 급격히 떨어지는 경향을 보이다가 사료(飼料) 급여 직전에 다시 상승하였다 3. 반추위내(反芻胃內) 총 휘발성지방산, 초산, 프로피온산 및 뷰틸산 농도는 F-S구가 가장 높았으며, 시간의 경과에 따른 경향은 1~3시간대에서 1차 peak를 이룬 후 9시간대에 2차 peak를 형성하였다. 4 시험사료(試驗飼料)의 일반성분 및 ADF소화율을 처리간에 영향이 없었으나 NDF소화율은 F-F구가 가장 높았다. 5. 질소축적율(窒素蓄積率)은 S-F구가 처리구중 가장 높았으며 F-F 및 F-S구가 가장 낮았다. 6. 시험사료(試驗飼料)의 대사율(代謝率), DCP, TDN, DE 및 ME 함량(含量)은 처리구간에 영향이 없었다. 7. 총균수(總菌數)는 사료급여후 3시간때 까지 전처리구 공히 증가하였다가 점차 감소하였고, 전체적으로 보면 F-F급여구가 $7.16{\times}10^{11}$ 으로 가장 많았으며 F-S구가 $2.85{\times}10^{11}$ 으로 가장 적었다. 8. Cellulolytic박테리아 수(數)는 S-S급여구가 다른 급여구보다 많았으며, 그 외 기능별 미생물수(微生物數)는 처리간에 차이를 볼 수 없었다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.79-82
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• 2003

An ionomer is defined as an ion-containing polymer with a small amount (usually up to 10-15 mol%) of ionic groups along the backbone chains or as pendant groups. Ionomers have been extensively studied because of the significant changes in their physical properties due to the formation of ionic aggregates, such as enhanced mechanical properties, high melt viscosity, and increased thermal properties.$\^$1-5/ Although there have been many studies of ionomers, the crystallization behaviour of degradable ionomers is still not understood. (omitted)

• Asian-Australasian Journal of Animal Sciences
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• 제14권7호
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• pp.974-978
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• 2001

The effect of three varying ratios (high, medium and low) of Rumen Degradable Protein (RDP) to Undegradable Dietary Protein (UDP) of 37:63, 52:48 and 70:30 in iso-nitrogenous and iso-caloric concentrate mixtures on rumen fermentation profile was studied using rumen fistulated Jersey crossbred cows. Rumen pH and ammonia nitrogen concentration were found to be lower with a concentrate mixture containing a higher UDP level of 63.38% when compared with those having medium and low UDP levels of 47.55 and 29.75%, respectively, at all post feeding intervals. Total volatile fatty acid concentration as well as concentrations of individual fatty acids viz., acetate, propionate and butyrate were also found higher in animals fed concentrate mixture with the highest UDP level.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.725-730
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• 1996

In this work, the software behavior under memory faults in operation phase is modeled and simulated using the stochastic activity network, generalized stochastic Petri nets. This networks permit the representation of concurrency, timeliness, fault tolerance, and degradable performance of system and provide a means for determining the stochastic behavior of a complex system. We estimate the reliability of an application software in the digitized system in nuclear power plants and show the sensitivity of the software reliability to the major physical parameters which affect the software failure in normal operation phase. We found that the effects of the hardware faults on the software failure should be considered for predicting the software dependability accurately in operation phase.

• Journal of Microbiology and Biotechnology
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• 제7권4호
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• pp.237-241
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• 1997

Two isolated strains, Comamonas testosteroni CPW301 and Arthrobacter ureafaciens CPR706, were able to use 4-chlorophenol (4-CP) as a sole carbon and energy source. CPW301 was found to degrade 4-CP via a meta-cleavage pathway in which the chloro-substituent was eliminated even when 4-chlorocatechol was cleaved by the catechol 2, 3-dioxygenase. In contrast, CPR706 removed chloride from 4-CP prior to the ring-fission reaction, producing hydroquinone as a transient intermediate during 4-CP degradation. CPR706 exhibited much higher tolerance for 4-CP than CPW301, which was indicated by the maximum degradable concentration and degradation rate.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.121-122
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• 2006

Paralleled with the development of new materials we need to develop methods and techniques to reveal the environmental interaction and impact of the new materials. Small changes in the chemical structure or product formulation may render the product less environmentally adaptable. Degradation products formed from PLLA were identified after aging in different environments and their assimilation in the biotic environment was shown. Green and degradable hydrogels could be designed from renewable hemicelluloses and lactic acid. Hemicelluloses are a renewable and highly interesting raw material source for new green polymers.

• Advanced Composite Materials
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• 제18권2호
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• pp.167-185
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• 2009

Environmental problems caused by extensive use of polymeric materials arise mainly due to lack of landfill space and depletion of finite natural resources of fossil raw materials like petroleum or natural gas. The substitution of synthetic petroleum-based resins with natural biodegradable resins appears to be one appropriate measure to remedy the above-mentioned situation. This study presents the development of a composite that uses environmentally degradable starch-based resin as matrix and natural mineral basalt fibres as reinforcement, and investigates the fibre's and the composite's mechanical properties. The tensile strength of single basalt fibres was verified by means of single fibre tensile tests and statistically investigated by means of a Weibull analysis. Prepreg sheets were manufactured by means of a modified doctor blade system and hot power press. The sheets were used to manufacture specimens with fibre volume contents ranging from 33% to 61%. Specimens were tested for tensile strength, flexural strength and interlaminar shear strength. Composites manufactured during this study exhibited tensile and flexural strength of up to 517 MPa and 157 MPa, respectively.

• Elastomers and Composites
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• 제34권4호
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• pp.292-298
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• 1999

Lactide oligomer with number averagae molecular weight of 460 was synthesized and reacted with poly(oxyteramethylene)glycol(PTMG, Mn = 650) to obtain oligolactide oligomer-terminated PTMG. Polyurethanes were synthesized from the oligolactide-terminated PTMG, 4,4'-diphenylmethane diisocyanate, and 1,4-butanediol. The mechanical and thermal properties of the polyurethanes and PTMG based polyurethane as control were measured by means of DSC and tensile tester. Degradation behavior of these polyurethanes put into a compost was evaluated by variation of mechanical properties, surface state, and weight loss. Modulus and weight significantly decreased with increasing time. The surface of the oligolactide polyurethane put into the compost during 6 weeks had a number of voids. On the other hand, These properties of the PTMG based polyurethane as control did not change. These results suggest that the novel polyurethanes incorporated oligolactide easily degrade under biodegradable condition.