• Title/Summary/Keyword: honogeneous

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Condensation processes in transonic two-phase flows of saturated humid air using a small-disturbance model (미교란 모델을 이용한 포화 습공기 천음속 2상 유동에서의 응축현상)

  • Lee, Jang-Chang;Zvi Rusak
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.6
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    • pp.23-29
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    • 2003
  • Transonic two-phase flow of Saturated humid air, in which relative humidity is 100%, with various condensation processes around thin airfoils is investigated. The study uses an extended transonic small-disturbance(TSD) model of Rusak and Lee [11, 12] which includes effects of heat addition to the flow due to condensation. Two possible limit types of condensation processes are considered. In the nonequilibrium and homogeneous process, the condensate mass fraction is calculated according to classical nucleation and droplet growth rate models. In the equilibrium process, the condensate mass fraction is calculated by assuming an isentropic process. The flow and condensation equations are solved numerical1y by iterative computations. Results under same upstream conditions describe the flow structure, field of condensate, and pressure distribution on airfoil's surfaces. It is found that flow characteristics, such as position and strength of shock waves and airfoil’s pressure distribution, are different for the two condensation processes. Yet, in each case, heat addition as a result of condensation causes significant changes in flow behavior and affects the aerodynamic performance of airfoils.

The Radiation Protection effect of Tabebuia Avellanedae Extract on the Prostate in Male Rats (수컷 쥐 전립선에 대한 타히보 추출물의 방사선 방호효과 연구)

  • Jeon, Chan-hee;Kim, Jang-Oh;Lee, Yoon-Ji;Lee, Ji-Eun;Lee, Chang-Ho;Min, Byung-In
    • Journal of the Korean Society of Radiology
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    • v.14 no.6
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    • pp.755-762
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    • 2020
  • This study is desinged to examine the effects of Taheebo(Tabebuia avellanedae) extract on the prostate of male rats as a natural radiation protection agent. Taheebo extract is well known to inhibit cell growth for the cell lines of breast and prostate cancer. In this study, the X-ray 7 Gy was irradiated in the prostate of male rat to identify radiation protection effects by Taheebo Extracts, 1, 7, and 21 Days later, hematological changes, external toxicity assessments(LDH), antioxidant enzyme(SOD) activity changes and tissue change were observed. IR+TH group showed greater lymphocyte levels than the irradiation group, which is believed to affect the hematopoietic immune system's resilience. As a results of the external toxicity assessment, Taheebo extract's toxicity is maximum 18.128±5.16%, minimum 13.6945±4.43%. Taheebo is considered to be of little toxicity. The composition of prostate cell nuclei and cytoplasm in Control and TH group was honogeneous, whereas the cell nucleus cohesion in the prostate in irradiation group and inflammatory reactions in cytoplasm were shown. IR+TH group showed less inflammatory reactions of cytoplasm in the prostate than in the radiation irradiation group, but showed a cohesive phenomenon of cell nuclei. It is judged that Taheebo extract has radiation protection against prostate cells.