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  • 1
    Electronic Resource
    Electronic Resource
    Vortex pair annihilation in Taylor wavy-vortex flow (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 7-9 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have made precision measurements of the vortex pair size and wavy mode amplitude of vortices in wavy Taylor–Couette vortex flow. These results are compared to a model advanced by Park and Crawford to account for expulsion of vortex pairs as the Reynolds number is increased in the wavy-vortex regime.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865129
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal excitation of waves on quantized vortices (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 498-504 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We consider the problem of the thermal excitation of vortex waves on quantized vortex lines and rings. We discover that this problem, which has been largely neglected in the past, apparently presents a "free energy catastrophe'' above about 1.85 K; that is, if one naively proceeds to compute the thermally induced vortex waves on rings or lines, the entropy of the waves becomes so large that the free energy of vortices is driven negative, and superfluidity could not exist. Various mechanisms for eliminating this problem are considered; it appears to be necessary to consider the relevant system to be the vortex plus the bath in order to avoid double counting of states. We comment on the relevance of this calculation to the problem of thermally induced nucleation of vortices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865113
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  • 3
    Electronic Resource
    Electronic Resource
    Cryogenic separation of methane from other hydrocarbons in air (1974)
    s.l. : American Chemical Society
    Environmental science & technology 8 (1974), S. 671-673 
    Details
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/es60092a004
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  • 4
    Electronic Resource
    Electronic Resource
    Feasibility study of condensation flue gas cleaning (CFGC) system (1978)
    s.l. : American Chemical Society
    Environmental science & technology 12 (1978), S. 1183-1188 
    Details
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/es60146a010
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of a coriolis force on Taylor-Couette flow (1991)
    Springer
    Journal of statistical physics 64 (1991), S. 913-926 
    Details
    ISSN: 1572-9613
    Keywords: Taylor-Couette flow ; Coriolis force ; onset of instability ; direct transition to turbulence ; tilted Taylor vortex flow ; Navier-Stokes equation in a rotating reference frame
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Taylor-Couette flow subject to a Coriolis force is studied experimentally and numerically. In the experiment, the Couette apparatus is mounted on a turntable with the axis of the cylinders orthogonal to the rotation vector of the turntable. The Coriolis force stabilizes the fluid against the onset of Taylor vortices and alters the velocity fields, both above and below the transition from the initial flow. At small dimensionless turntable frequenciesΩ, the transition yields time-independent Taylor vortices which are tilted with respect to the cylinder axis. At largerΩ there is a direct transition to turbulence. We determine the first-order correction to the classical Couette initial flow, to account for the effects of the Coriolis force, by expanding in powers ofΩ. We present numerical results for the axial velocity (the only nonvanishing correction term to orderΩ) in the infinite-cylinder approximation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01048804
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  • 6
    Electronic Resource
    Electronic Resource
    Emerging issues in helium turbulence (1995)
    Springer
    Journal of low temperature physics 100 (1995), S. 385-413 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It has been appreciated recently that because helium has the lowest viscosity of any known material, it can be used in reaching the very highest Reynolds numbers and Rayleigh numbers. Critical helium gas, helium I and helium II are all candidates for such uses. Helium gas and helium I are classical fluids and the advantage stems solely from their low kinematic viscosity. Helium II obeys two-fluid equations and their use in turbulence investigations is under study. This article provides a brief introduction and review of this topic, outlining some of the progress already made and questions which need to be resolved as this relatively new field of investigation evolves. A summary of instrumentation available is included.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00751517
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  • 7
    Electronic Resource
    Electronic Resource
    Scattering and binding of rotons (1974)
    Springer
    Journal of low temperature physics 15 (1974), S. 1-27 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The interaction of rotons is studied by a direct examination of their orbital dynamics. It is found that upon representing rotons as point dipoles in the superfluid, obeying the Landau dispersion relation, negative energy states occur, some of which are stable and some unstable. The binding energy and effective mass of these states are found, but are too large to agree with experiment. Improvements in the Hamiltonian are explored which recognize the actual dispersion curve as well as higher moments in the interaction. Both modifications lead to binding energy and effective mass in better agreement with experiment. Scattering is also examined, and one finds that a representative roton-roton cross section may be obtained in the dipole approximation, again using Landau dispersion. The scattering cross section is shown to be in satisfactory agreement with neutron linewidths in the roton-dominated region, as well as the roton contribution to the shear viscosity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655620
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  • 8
    Electronic Resource
    Electronic Resource
    An experiment to investigate the superfluid transition in a confined planar geometry (1998)
    Springer
    Journal of low temperature physics 113 (1998), S. 441-446 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a progress report on our investigation of finite size effects on the superfluid transition. In our experiment, the helium is confined between the parallel plates of a carefully constructed capacitor. We measure the dielectric constant as a function of temperature, from which we can calculate the thermal expansivity. We discuss some of the following important features of our experiment: The capacitor, built in collaboration with the Chex experiment, gives us a simple, well defined planar geometry, extremely flat surfaces, and a sub-micron gap. A low temperature audio-frequency preamp improves the sensitivity of the capacitance measurement. A high resolution paramagnetic salt thermometer, also from Chex, enables us to work extremely close to the lambda point. We also present a novel design for a simple low temperature burst disc that is part of our apparatus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022548011314
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  • 9
    Electronic Resource
    Electronic Resource
    A theory of temperature-dependent energy levels: Thermodynamic properties of He II (1977)
    Springer
    Journal of low temperature physics 27 (1977), S. 687-736 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The statistical mechanics of interacting bosons is considered for cases where the interactions are sufficiently strong that the observed energy levels are dependent upon temperature. An approximate method is developed to handle the theory when energy levels are known from experiment. The results are applied to the thermodynamic properties of He II using Landau's theory of elementary excitations. This theory is assessed in several levels of approximation, and the results are compared extensively to measured thermodynamic properties. The relationship of neutron inelastic scattering measurements to these problems is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655704
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  • 10
    Electronic Resource
    Electronic Resource
    Vortex dynamics and scaling in turbulent counterflowing helium II (1985)
    Springer
    Journal of low temperature physics 61 (1985), S. 363-399 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Dimensional analysis of the equation of motion for a vortex line yields a dimensionless velocity which controls the development of a vortex line tangle in counterflowing helium II. This scaling is applied to measurements of critical velocities and ratios of line density to counterflow velocity from experiments in channels of different sizes; substantially better agreement is found than previously reported. An asymptotic relationship is derived between line density and counterflow velocity which fits new and existing data remarkably well. This relationship is used to explain the increase in the power law of the Gorter-Mellink relationship between temperature gradient and heat flux near the λ point.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00683692
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