• 제목/요약/키워드: environment technology

검색결과 23,470건 처리시간 0.041초

Butyric Acid Fermentation of Sodium Hydroxide Pretreated Rice Straw with Undefined Mixed Culture

  • Ai, Binling;Li, Jianzheng;Chi, Xue;Meng, Jia;Liu, Chong;Shi, En
    • Journal of Microbiology and Biotechnology
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    • 제24권5호
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    • pp.629-638
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    • 2014
  • This study describes an alternative mixed culture fermentation technology to anaerobically convert lignocellulosic biomass into butyric acid, a valuable product with wide application, without supplementary cellulolytic enzymes. Rice straw was soaked in 1% NaOH solution to increase digestibility. Among the tested pretreatment conditions, soaking rice straw at $50^{\circ}C$ for 72 h removed ~66% of the lignin, but retained ~84% of the cellulose and ~71% of the hemicellulose. By using an undefined cellulose-degrading butyrate-producing microbial community as butyric acid producer in batch fermentation, about 6 g/l of butyric acid was produced from the pretreated rice straw, which accounted for ~76% of the total volatile fatty acids. In the repeated-batch operation, the butyric acid production declined batch by batch, which was most possibly caused by the shift of microbial community structure monitored by denaturing gradient gel electrophoresis. In this study, batch operation was observed to be more suitable for butyric acid production.

$H_2/Ar$ 혼합기체의 PSA 공정 실험과 모사 (Experiment and Simulation of PSA Process for $H_2/Ar$ Mixtures gas)

  • 강석현;정병만;최현우;김성현;이병권;최대기
    • 한국수소및신에너지학회논문집
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    • 제16권2호
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    • pp.180-190
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    • 2005
  • The PSA cycle was performed for the separation of binary gas mixture $H_2/Ar$ (80%/20%) using the six-step two-bed process. Adsorption equilibrium contains a LRC model for equilibrium adsorption isotherms and a LDF model for mass transfer. Aspen ADSIM, simulator was applied to predict the separation performance. The effect of cycle parameters such as feed rate, adsorption pressure and P/F ratio on the separation of hydrogen has been studied in experiment and simulation. In the results, maximize the recovery of hydrogen as a high purity was 13LPM feed flowrate, 120sec adsorption time, 11atm adsorption pressure and 0.1 P/F ratio in a cyclic steady-state come out since 10th cycle.

Review of Landfill Leachate Treatment

  • Wang, Yun;Fang, Qin;Jin, Jie
    • 도시과학
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    • 제8권2호
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    • pp.41-45
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    • 2019
  • The treatment method of leachate was increasing with the progress of science and technology, the management system was more perfect. The paper gathered so far the leachate treatment technology, including physical, chemical and biological treatment technology, and found the technology to be improved, the paper expounds the advantages and disadvantages of each method, applicable scope in the future, leachate treatment technology.

감마선 조사법을 이용한 전기방사 나노/마이크로 섬유 지지체의 표면 기능화 (Functionalization of Electrospun Nano/Micro-fibrous Scaffolds Using Gamma-ray Irradiation)

  • 임종영;신영민;최종배;정진오;권희정;정성린;박종석;임윤묵
    • 방사선산업학회지
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    • 제7권1호
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    • pp.45-49
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    • 2013
  • In tissue engineering application, a fibrous structure of scaffolds has been issued as an alternative system to regulate cell survival and tissue regeneration, and electrospinning technique has been popularly used to generate fibrous meshes or sheets mimicking the structure of native extracellular matrix (ECM). However, recent strategy in the scaffold development is expanded to provide the structural property as well as a biological property of native ECM, a variety of surface modification techniques have been used to introduce biological property. In this study, we developed biomimetic poly(L-lactide-co-${\varepsilon}$-caprolactone) (PLCL) nano- and micro-fibrous scaffolds as a unique platform with structural and biological properties with native ECM using electrospinning method and gamma-ray irradiation. Surface morphology of the scaffolds was observed by scanning electron microscopy, and alteration of surface property was evaluated with toluidine blue O staining, water contact angle measurement and ATR-FTIR analysis.

Scanning Rayleigh Doppler Lidar for Wind Profiling Based on Non-polarized Beam Splitter Cube Optically Contacted FPI

  • Zheng, Jun;Sun, Dongsong;Chen, Tingdi;Zhao, Ruocan;Han, Yuli;Li, Zimu;Zhou, Anran;Zhang, Nannan
    • Current Optics and Photonics
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    • 제2권2호
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    • pp.195-202
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    • 2018
  • A Scanning Rayleigh Doppler lidar for wind profiling based on a non-polarized beam splitter cube optically contacted FPI is developed for wind measurement from high troposphere to low stratosphere in 5-35 km. Non-polarized beam splitter cube optically contacted to the FPI are used for a stable optical receiver. Zero Doppler shift correction is used to correct for laser or FPI frequency jitter and drift and the timing sequence is designed. Stability of the receiver for Doppler shift discrimination is validated by measuring the transmissions of FPI in different days and analyzed the response functions. The maximal relative wind deviation due to the stability of the optical receiver is about 4.1% and the standard deviation of wind velocity is 1.6% due to the stability. Wind measurement comparison experiments were carried out in Jiuquan ($39.741^{\circ}N$, $98.495^{\circ}E$), Gansu province of China in 2015, showing good agreement with radiosonde result data. Continuous wind field observation was performed from October 16th to November 12th and semi-continuous wind field of 19 nights are presented.

바이오필름 반응기상에서 수소 이용성 독립영양생물을 이용한 고농도 탈질 반응 (Autohydrogenotrophic Denitrification of High Nitrate Concentration in a Glass Bead Biofilm Reactor)

  • 박호일;김지성;김동건;박대원
    • 한국물환경학회지
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    • 제20권3호
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    • pp.236-240
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    • 2004
  • Autohydrogenotrophic denitrification of high nitrate concentration contaminated wastewater in a batch-scale biofilm reactor has been investigated. High nitrate concentration decreased as pH increased from 7.01 to 9.45. The high nitrate concentrations continuously decrease from $150mg.l^{-1}$ to $0mg.l^{-1}$. Nitrite concentrations increase at about two-thirds way through the denitrification process and thereafter it decreases with time. Autohydrogenotrophic denitrification of high nitrate concentration is passible to use drinking water as well as wastewater, and to deal with wastewater treatment by hetrotrophic denitrification.