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Andrea Gabrielli - One of the best experts on this subject based on the ideXlab platform.

Yuxin Zhao - One of the best experts on this subject based on the ideXlab platform.

  • application of free interaction theory in swept shock wave turbulent boundary layer interactions
    Journal of Visualization, 2018
    Co-Authors: Gang He, Jin Zhou, Yuxin Zhao
    Abstract:

    Fin-generated swept shock wave/turbulent boundary layer interactions were experimentally investigated via nanoparticle-based planar laser scattering method, surface oil flow visualizations, surface Pressure measurements, and particle image velocimetry. Surface Plateau Pressure is also theoretically predicted. The Plateau Pressure of present quasi-conical swept shock interaction is dependent on the local skin friction coefficient and normal Mach number component, and can be predicted per a criterion deduced from free interaction theory. Visualizations and surface Pressure measurements confirm that the surface Plateau Pressure data are equal to the Pressure downstream of the separation shock; the upstream influence line is parallel to the impingement line of the separation shock on the flat plate. These observations support the free interaction theory as-applied to quasi-conical swept shock interactions.

  • Application of free interaction theory in swept shock wave/turbulent boundary layer interactions
    Journal of Visualization, 2017
    Co-Authors: Jin Zhou, Yuxin Zhao
    Abstract:

    Fin-generated swept shock wave/turbulent boundary layer interactions were experimentally investigated via nanoparticle-based planar laser scattering method, surface oil flow visualizations, surface Pressure measurements, and particle image velocimetry. Surface Plateau Pressure is also theoretically predicted. The Plateau Pressure of present quasi-conical swept shock interaction is dependent on the local skin friction coefficient and normal Mach number component, and can be predicted per a criterion deduced from free interaction theory. Visualizations and surface Pressure measurements confirm that the surface Plateau Pressure data are equal to the Pressure downstream of the separation shock; the upstream influence line is parallel to the impingement line of the separation shock on the flat plate. These observations support the free interaction theory as-applied to quasi-conical swept shock interactions.

Jaiyoung Lee - One of the best experts on this subject based on the ideXlab platform.

  • hydrogen storage properties of vanadium based b c c solid solution metal hydrides
    Journal of Alloys and Compounds, 2003
    Co-Authors: Chanyeol Seo, Paul S Lee, Jinho Kim, Jaiyoung Lee
    Abstract:

    Abstract On the basis of literature reports, several series of vanadium-based solid solutions with a b.c.c. structure were prepared and their hydrogen storage properties were studied in order to develop alloys with high hydrogen capacity and low cost. The V–Ti–Cr alloys were examined by adding other b.c.c. elements (Mn and Fe) and adjusting the corresponding compositions. Increasing the Cr content and the addition of Mn increased the Plateau Pressure due to lattice contraction, which is beneficial for reducing the first Plateau region, although it decreased the maximum hydrogen storage capacity. Furthermore, Mn is an effective element to flatten the Plateau Pressure. The alloys containing Fe were found to be difficult to activate. A V 0.375 Ti 0.25 Cr 0.30 Mn 0.075 alloy was developed which exhibited an effective hydrogen capacity of 2.2 wt% H after annealing at 1300 °C for 1 h.

  • Self-discharge mechanism of Vanadium–Titanium metal hydride electrodes for Ni–MH rechargeable battery
    Journal of Alloys and Compounds, 1998
    Co-Authors: Kuk-jin Jang, Jae-han Jung, Dong-myung Kim, Jaiyoung Lee
    Abstract:

    In order to investigate the effect of the equilibrium hydrogen Pressure (Plateau Pressure) of metal hydride (MH) alloys on self-discharge behavior, V0.9Ti0.1 alloys having multi-Plateau Pressures (low and high Plateau Pressures) have been used as working electrodes in a half cell. The thermal desorption experiment and open-circuit potential monitoring were conducted to observe the self-discharge behavior of the electrode. From the thermal desorption spectra of the fully charged and discharged V0.9Ti0.1 electrode (to −0.7 V versus Hg/HgO), it is found that only the higher one of the two Plateau Pressure regions of the V0.9Ti0.1 electrodes is electrochemically useful for battery application. But the open-circuit potential change and thermal desorption spectra of the V0.9Ti0.1 electrode after various open-circuit storage periods prove that the self-discharge behavior is attributed to the hydrogen desorption from the low Plateau Pressure (10−8 atm) as well as the high Plateau Pressure (0.1 atm). Therefore, it is suggested that the self-discharge behavior of V0.9Ti0.1 electrodes can not be effectively suppressed by reducing the Plateau Pressure of alloys through alloy modification. In addition, the Pressure–composition–isotherms (P–C–T) of the low Pressure region can be estimated by using the open-circuit potential corresponding to this region in Nernst's equation.

  • Self-discharge mechanism of vanadium-titanium metal hydride electrodesfor Ni-MH rechargeable battery
    Metals and Materials, 1997
    Co-Authors: Jae-han Jung, Han-ho Lee, Kuk-jin Jang, Jaiyoung Lee
    Abstract:

    In order to investigate the effect of the equilibrium hydrogen Pressure (Plateau Pressure) of metal hydride (MH) alloys on self-discharge behavior, V09Ti01 alloys having multi-Plateau Pressures (the low and high Plateau Pressure) have been used as working electrodes in a half cell. A thermal desorption experiment and open-circuit potential monitoring were conducted to observe the self-discharge behavior of the electrodes. From the thermal desorption spectra of fully charged and discharged V09Ti01 electrodes (to-0.7 V vs. Hg/ HgO), it was found that only the high Plateau Pressure region from V09Ti01 electrodes is electrochemically useful in battery application. However, the open-circuit potential change and thermal desorption spectra of V09Ti01 electrodes after various open-circuit storage periods prove that self-discharge behavior is caused by hydrogen desorption from the low Plateau Pressure region (10-8 atm) as well as the high Plateau Pressure region (0.1 atm). Therefore, it is suggested that the self-discharge behavior of V09Ti01 electrodes cannot be suppressed effectively by reduction of the Plateau Pressure of alloys through alloy modification.In addition, the Pressure-composition-isotherms (P-C-T) of the low Pressure region can be estimated by using the open-circuit potential corresponding to this region in Nernst’s equation.

Nawar Alrawas - One of the best experts on this subject based on the ideXlab platform.

Michele Gupta - One of the best experts on this subject based on the ideXlab platform.

  • consequences of helium production from the radioactive decay of tritium on the properties of palladium tritide
    Physical Review B, 2002
    Co-Authors: Raju P Gupta, Michele Gupta
    Abstract:

    Tritium is an element of considerable interest in the nuclear industry. Since it is radioactive, it needs to be stored in a safe but easily recoverable manner. It is an isotope of H, and hence some of the techniques used for hydrogen storage can be employed, the safest being its storage in the form of a tritide. However, in contrast to the case of hydrogen, tritium decays into 3 He and thus modifies the properties of the tritide. The recoil energy of 3 He in this decay process is very small, ∼ 1.03 eV, and not enough for atomic displacements to occur. We show in this paper, on the basis of our electronic structure calculations, that in the case of PdT, the 3 He produced from the radioactive decay of tritium, although not soluble in the tritide, can be easily retained, in a metastable state, in surprisingly large quantities at the octahedral interstitial sites where it is born. This can explain the expansion of the lattice parameter, the lowering of the Plateau Pressure, and the fragility of the tritide observed experimentally. We also find that the lowering of the Plateau Pressure is not entirely due to the lattice expansion as usually assumed and that electronic interactions also play a role.