• Title/Summary/Keyword: CMBR

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ANISOTROPY OF CMBR AND GAUGE INVARIANT COSMIC PERTURBATION THEORIES - SOME AMBIGUITIES AND PROBLEMS

  • XU CHONGMING;WU XUEJUN
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.17-18
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    • 1996
  • COBE's results on the anisotropy of the cosmic microwave background radiation (CMBR) is discussed. Some ambiguities in the linear GI cosmic perturbation theory are clarified. The problem of the last scattering surface and the deficiencies of the linear cosmic perturbation theory are mentioned. The possible ways to overcome the theoretical difficulties are discussed also.

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CMBR FLUCTUATIONS IN THE BIANCHI TYPE I SPACETIME: THE EFFECTS OF GRAVITATIONAL WAVES (비앙키 I 형 시공간 속의 CMBR 흔들림: 중력파의 영향)

  • Song, D.J.
    • Publications of The Korean Astronomical Society
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    • v.18 no.1
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    • pp.1-9
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    • 2003
  • In the framework of linear perturbation theory and linear approximation of spacetime anisotropy, we investigated the formulae for the CMBR temperature anisotropy and fluctuation spectrum which have their origin in the primordial tensor perturbations of the perturbed Bianchi type I universe model. The resulting formulae were compared with those of the flat Friedmann model.

TEMPERATURE FLUCTUATION AND EXPECTED LIMIT OF HUBBLE PARAMETER IN THE SELF-CONSISTENT MODEL

  • Morcos, A.B.
    • Journal of The Korean Astronomical Society
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    • v.39 no.4
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    • pp.81-87
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    • 2006
  • A relation between temperature and time has been constructed in the self-consistent model(SCM). This relation is used to calculate the a CMBR temperature. This temperature has been found to be 2.9K. The temperature gradient of microwave background radiation(CMBR) is calculated in the Self Consistent Model. Two relations between Hubble parameter and time derivative of the temperature, have been presented in two different cases. In the first case the temperature is treated as a function of time only, while in the other one, it is assumed to be a function in time and solid angle, beside the assumption that the universe expands adiabatically.

Recent advances and future potential of anaerobic ceramic membrane bioreactors for wastewater treatment: A review

  • Cha, Minju;Kim, Soyoun;Park, Chanhyuk
    • Membrane and Water Treatment
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    • v.11 no.1
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    • pp.31-39
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    • 2020
  • Anaerobic membrane bioreactor (AnMBR) treatment has been widely studied in recent years because of the potential for production of bio-energy from wastewater and energy-positive operation of wastewater treatment plants. Several AnMBR systems, including those that incorporate ceramic membranes, take advantage of enhanced water permeability and low membrane fouling potentials. Given that differences in the ceramic membranes may influence the results of AnMBR studies, relevant details are discussed in this review, which focuses on the profiles of common ceramic membranes used in AnMBR, treatment and filtration performances of different anaerobic ceramic membrane bioreactors (AnCMBRs), and the membrane fouling mitigation methods available for effective AnCMBRs operation. The aim of this review is to provide a comprehensive summary of AnCMBR performance, feed wastewater characteristics, operating conditions, and the methods available for effective fouling mitigation.