• Title/Summary/Keyword: Degradation

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Microbacterium esteraromaticum CS3-1의 toluene 분해능에 미치는 benzene, ethylbenzene, xylene의 영향

  • Jeon, Yeon-Sin;Lee, Eun-Yeong;Jo, Gyeong-Suk;Ryu, Hui-Uk
    • 한국생물공학회:학술대회논문집
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    • 2000.11a
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    • pp.179-182
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    • 2000
  • Toluene-degrading bacterium, Microbacterium esteraromaticum CS3-1 was isolated from the biofilter for the removal of BTEX. Microbacterium esteraromaticum CS3-1 was shown to utilize toluene as a primary carbon and energy source. Effect of mixed BTEX gases on toluene degradation rate by M. esteraromaticum CS3-1 was investigated in this study. Toluene degradation rate was 2.26(only toluene), 2.06(toluene+benzene), 2.57(toluene+ethylbenzene), and 4.74(toluene+xylene) mmole $toluene\;{\cdot}\;g-DCW^{-1}\;{\cdot}\;h^{-1}$. Toluene degradation rate was 2.26(only toluene), 1.23(toluene+benzene+ethylbenzene), 1.52 (toluene+ethylbenzene+xylene), and 1.76(toluene+benzene+ethylbenzene+xylene) mmole $toluene\;{\cdot}\;g-DCW^{-1}\;{\cdot}\;h^{-1}$. The presence of BTEX compounds over three mixtures had a negative effect on toluene degradation rate. Toluene degradation rates were enhanced by the presence of ethylbenzene or xylene, whereas the presence of benzene had a negative effect on toluene degradation rate in comparison with toluene degradation rate when only toluene is existent.

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Thermal Degradation and Cyclodepolymerization of Poly(ethylene terephthalate-co-isophthalate)s

  • Yoo, Dong Il;Shin, Younsook;Youk, Ji Ho
    • Fibers and Polymers
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    • v.2 no.2
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    • pp.75-80
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    • 2001
  • The thermal degradation of poly(ethylene terephthalate-co-isophthalate)s (PETIs) is investigated by using isothermal thermogravimetric analysis at the temperature range of 280-31$0^{\circ}C$. The degradation rate of PETIs is increased as the mole ratio of ethylene isophthaloyl (EI) units in PETIs increases. The activation energies for the thermal degradation of poly(ethylene terephthalate), PETI(5/5), and poly(ethylene isophthalate) are 33.4, 16.6, and 8.9 kcal/mole, respectively. The degradation rate of PETIs is influenced by their volatile cyclic oligomer components formed during the polymerization and the thermal degradation. It is simulated by the rotational isomeric state model that the content of cyclic dimer in PETIs, which is the most volatile cyclic oligomer component, increases with the EI units in PETIs.

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Evaluation of Material Degradation Using Electrical Resistivity Method (전기비저항법을 이용한 재료열화 평가)

  • Kim, Jeong-Pyo;Bae, Bong-Kook;Kim, Dong-Joong;Seok, Chang-Sung
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.129-136
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    • 2001
  • The remaining life estimation for the aged components in power plants as well as chemical plants are very important beacuse mechanical properties of the components are degraded with time of service exposure in high temperature. Since it is difficult to take specimens from the operating components to evaluate mechanical properties of components, nondestructive techniques are needed to estimate the degradation. In this study, test materials with 4 different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C$. And the DC potential drop method and destructive methods such as tensile, $K_{IC}$ and hardness tests were used in order to evaluate the degradation of 1Cr-1Mo-0.25V steels. The objective of this study is to investigate the possibility of the application of DCPD method to estimate the material degradation, and to analyse the relationship between the electrical resistivity and the degree of material degradation.

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DEGRADATION OF NUCLEIC ACIDS BY CELL-FREE EXTRACT OF MIXED RUMEN PROTOZOA OF BUFFALO RUMEN

  • Sinha, P.R.;Dutta, S.M..
    • Asian-Australasian Journal of Animal Sciences
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    • v.1 no.4
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    • pp.219-222
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    • 1988
  • Degradation of deoxyribonucleic acid(DNA) and ribonucleic acid(RNA) by cell-free extract of mixed rumen protozoa of buffalo rumen was investigated. DNA was observed to be degraded rapidly during an initial incubation period of 2 hr with simultaneous appearance of degradation products. RNA on the other hand recorded a rapid degradation during an initial incubation period of 1 hr. RNA degradation products appeared upto an incubation period of 2 hr. DNA was observed to degrade into oligo- and mononucleotides. pyrimidine nucleosides, purine nucleoside adenosine and bases xanthine, hypoxanthine and thymine. Degradation products of RNA comprised of pyrimidine nucleosides, purine nucleoside, adenosine and bases xanthine, hypoxanthine and uracil besides oligo- and mononucleotides.

Design of Intelligent Insulation Degradation Sensor

  • Kim, Yi-Gon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.2 no.3
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    • pp.191-193
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    • 2002
  • Insulation aging diagnosis system provides early warning in regard to electrical equipment defects. Early warning is very important in that it can avoid great losses resulting from unexpected shutdown of the production line. For solving this problem, many researchers proposed a method that diagnose power plant by using partial discharge. In this paper, we design the intelligent sensor to diagnose insulation degradation state that uses a Microprocessor and Al. Proposed sensor has MCU that is used to diagnose insulation degradation and communicate with main IDD system. And we use a fuzzy model to diagnose insulation degradation.

Optimal Design of Accelerated Degradation Tests with Two Stress Variables in the Case that the Degradation Characteristic Follows Weibull Distribution (열화특성치가 와이블분포를 따르는 경우 두 가지 스트레스 변수를 고려한 가속열화시험의 최적 설계)

  • Lim, Heonsang;Kim, Yong Soo
    • Journal of Applied Reliability
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    • v.13 no.2
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    • pp.87-98
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    • 2013
  • Accelerated degradation tests (ADTs) measuring failure-related degradation characteristic at the accelerated condition are widely used to assess the reliability of highly reliable products. Often, however, little degradation could be observed even in single-stress ADTs due to the high reliability of test unit, and as a result poor estimate of the reliability may be obtained. ADTs with multiple stress variables can be employed to overcome such difficulties. In this paper, optimal ADT plans with two stress variables are developed assuming that the degradation characteristic follows Weibull distribution by determining the stress levels, the proportion of test units allocated to each stress level such that the asymptotic variance of the maximum likelihood estimator of the q-th quantile of the lifetime distribution at the use condition is minimized.

Effect of dielectric barrier discharge parameters on degradation efficiency of ethyl acetate

  • Deng, Xu;Lu, SiHeng;Zheng, Kun;Yu, ZhiMin
    • Journal of Urban Science
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    • v.8 no.2
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    • pp.13-18
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    • 2019
  • Using self-made coil dielectric barrier discharge reactor, the removal efficiency of ethyl acetate under simulated experimental parameters such as initial concentration of waste gas, total flow rate, relative humidity and voltage was investigated. The results show that the degradation rate of ethyl acetate increases with the increase of output voltage. When other conditions remain unchanged, the degradation rate decreases with the increase of initial concentration of ethyl acetate; with the increase of total flow rate, the degradation rate of ethyl acetate decreases; with the increase of relative humidity, the degradation rate first increases and then decreases, and when the relative humidity is 64%, the degradation efficiency is the highest.

Microbial Degradation and Toxicity of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine

  • Khan, Muhammad Imran;Lee, Jaejin;Park, Joonhong
    • Journal of Microbiology and Biotechnology
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    • v.22 no.10
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    • pp.1311-1323
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    • 2012
  • In the present work, current knowledge on the potential fate, microbial degradation, and toxicity of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was thoroughly reviewed, focusing on the toxicological assessment of a variety of potential RDX degradation pathways in bacteria and fungi. The present review on microbial degradation pathways and toxicities of degradation intermediates suggests that, among aerobic RDX degradation pathways, the one via denitration may be preferred in a toxicological perspective, and that among anaerobic pathways, those forming 4-nitro-2,4-diazabutanal (NDAB) via ring cleavage of 1-nitroso-3,5-dinitro-1,3,5-triazinane (MNX) may be toxicologically advantageous owing to its potential mineralization under partial or complete anoxic conditions. These findings provide important information on RDX-degrading microbial pathways, toxicologically most suitable to be stimulated in contaminated fields.

The Performance Degradation of Static Type Input Buffers due to Device Degradation (소자열화로 인한 Static 형 입력버퍼의 성능저하)

  • 김한기;윤병오
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.561-564
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    • 1998
  • This paper describes a performance degradation of static type input buffer due to the device degradation in menory devices using $0.8\mu\textrm{m}$ CMOS process. experimental results shows that the degradation of MOS device affects the Trip Point shift in static type input buffer. We have performed the spice simulation and calculated the Trip Point with model parameter and measurement data so that how much the Trip Point(VLT) variate.

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Effects of Cadmium on the Degradation of Butachlor Pollutant by Microorganism (Cadmium이 토양미생물에 의한 Butachlor 오염물질 분야에 미치는 영향)

  • 허태웅;정문호
    • Journal of Environmental Health Sciences
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    • v.20 no.3
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    • pp.78-84
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    • 1994
  • The effects of heavy metal, Cd on the degradation of the herbicide butachlor (N-Butoxymethyl-2-chlor-2',6'-diethylacetanilide) in soils were examined the laboratory. The degradation of the herbicide in soil was greatly inhibited by the amendment of the heavy metal, Cd. The inhibited rate of Cd concentration was high in the order of 30 ppm>20 ppm> 10 ppm>0 ppm. And tile degradation rate of butachlor was high in order of 80 $\mu$M>40 $\mu$M>20 $\mu$M. The effects of Cd on the degradation of the butachlor in soil varied with concentration of heavy metal and butachlor.

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