• Title/Summary/Keyword: technology and environment

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

  • Kang, Seok-Hyun;Jeong, Byung-Man;Choi, Hyun-Woo;Kim, Sung-Hyun;Lee, Byung-Kwon;Choi, Dae-Ki
    • Transactions of the Korean hydrogen and new energy society
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    • v.16 no.2
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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.

A Study on Isolation of BTEX Degrading Microorganism and Variation of BTEX Removal Efficiency and Microorganism Growth Rate According to Co-Culture (BTEX 분해미생물의 순수분리와 혼합 배양에 따른 기질 분해율 및 미생물 성장률 변화에 관한 연구)

  • Chung, Kyung-mi;Lee, Sang-hyup;Lee, Han-woong;Hong, Seok-won;Kim, Young-o;Choi, Yong-su;Yu, Myong-jin
    • Journal of Korean Society on Water Environment
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    • v.21 no.4
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    • pp.347-352
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    • 2005
  • The isolated microorganisms, Pseudomonas stutzeri, Raoultella planticola (Klebsiella), Serratia fonticola from petroleum contaminated soil were enriched on benzene, toluene, ethylbenzene, o-xylene as carbon and energy sources, respectively. And the degradation characteristics of BTEX was observed in the mixed BTEX substrates. We found that the BTEX in mixed substrates were degraded more than 50% by three isolated microorganisms. Among three isolated microorganisms, the highest degradation rate was observed in Pseudomonas stutzeri, but the degradation rate was different according to microorganisms. In order to increase the degradation efficiency, we applied the co-culture of isolated three microorganisms. The mixture rate of pseudomonas stutzeri : Raoultella planticola (Klebsiella) : Serratia fonticola was follows ; 1:2:1, 1:1:2, and 2:1:1, respectively. In two co-culture of 1:2:1 and 1:1:2, degradation rate was lower than isolated microorganisms. However, degradation rate became higher than isolated microorganisms and the degradation rate of benzene, toluene, and ethylene was more than 95% in co-culture of 2:1:1. The degradation rate increased through the co-culture of isolated microorganisms, however, the growth rate decreased. This was resulted from the substrate competition between microorganisms. The co-culture of microorganisms is a effective method to increase the degradation efficiency of BTEX and the co-culture mixing rate is a important factor for determination of degradation efficiency.

Review of Landfill Leachate Treatment

  • Wang, Yun;Fang, Qin;Jin, Jie
    • Journal of Urban Science
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    • v.8 no.2
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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.

Effect of the Repository Configuration on Radionuclide Transport with the Multi-compartment Model for the LILW Repository Performance

  • Park, Jin-Beak;Park, Joo-Wan;Kim, Chang-Lak;Joonhong Ahn;Daisuke Kawasaki
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.228-228
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    • 2004
  • Nuclear Environment Technology Institute (KHNP-NETEC) developed the conceptual design of the low and intermediate-level radioactive waste (LILW) repository. Among many engineering challenges, it is of particular importance to find out an optimum arrangement of near-surface disposal vaults in the repository area to minimize the radionuclide flux and concentration at the interface between the geo-sphere and bio-sphere. (omitted)

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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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    • v.24 no.5
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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.

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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    • v.2 no.2
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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.

Improved Performance of Microbial Fuel Cell Using Membrane-Electrode Assembly

  • PHAM THE HAl;JANG JAE KYUNG;MOON HYUN SOO;CHANG IN SEOP;KIM BYUNG HONG
    • Journal of Microbiology and Biotechnology
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    • v.15 no.2
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    • pp.438-441
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    • 2005
  • A mediator-less microbial fuel cell (MFC) was used to determine the performance effects of a membrane­electrode assembly (MEA). The MFC with an MEA generated a higher current with an increased coulomb yield when compared to an MFC with a separate cathode. Less oxygen was diffused through an MEA than through a Nafion membrane. The MFC performance was improved with a buffer, although a high-strength buffer reduced the performance.