3,494 research outputs found

    Sidereal anisotropy of cosmic rays

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    The data of the ionization chamber in Yakutsk for 1954 to 1984 are analyzed. A false sidereal variation caused by the second spherical harmonic in cosmic ray distribution was found and it has the amplitude 0.020 plus or minus 0.002%. The sidereal anisotropy with a very small amplitude (not more than 0.005%) was observed to exist

    Change of cosmic ray anisotropy with solar activity

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    Muon telescope data at various depths underground in Yakutsk within energy range 10 to 300 GeV for 1957 to 1984 are analyzed. The 22-year variation of the interplanetary magnetic field aligned component is found. The variation is caused by interaction of heliomagnetosphere with the local galactic field and interstellar wind

    Neutron - Mirror Neutron Oscillations: How Fast Might They Be?

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    We discuss the phenomenological implications of the neutron (n) oscillation into the mirror neutron (n'), a hypothetical particle exactly degenerate in mass with the neutron but sterile to normal matter. We show that the present experimental data allow a maximal n-n' oscillation in vacuum with a characteristic time τ\tau much shorter than the neutron lifetime, in fact as small as 1 sec. This phenomenon may manifest in neutron disappearance and regeneration experiments perfectly accessible to present experimental capabilities and may also have interesting astrophysical consequences, in particular for the propagation of ultra high energy cosmic rays.Comment: 4 pages, 1 figure; revtex; matches paper published by P.R.

    Relief and geology of the north polar region of the planet Venus

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    Description of topographic features is given for the North polar region of the planet Venus. Principal geomorphic types of terrain are characterized as well as their geologic relations. Relative ages of geologic units in Venus North polar region are discussed

    Neutron-antineutron Oscillations in the Trapping Box

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    We have reexamined the problem of nnˉn-\bar n oscillations for ultra-cold neutrons (UCN) confined within a trap. We have shown that the growth of the nˉ\bar n component with time is to a decent accuracy given by P(nˉ)=ϵnnˉ2tLt,P(\bar n)= \epsilon^2_{n\bar n} t_Lt, where ϵnnˉ\epsilon_{n\bar n} is the mixing parameter, tL1t_L\sim 1 sec in the neutron propagation time between subsequent collisions with the trap walls. Possible corrections to this law and open questions are discussed.Comment: 11 pages, LaTeX2

    Dynamics of the magnetic flux trapped in fractal clusters of normal phase in a superconductor

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    The influence of geometry and morphology of superconducting structure on critical currents and magnetic flux trapping in percolative type-II superconductor is considered. The superconductor contains the clusters of a normal phase, which act as pinning centers. It is found that such clusters have significant fractal properties. The main features of these clusters are studied in detail: the cluster statistics is analyzed; the fractal dimension of their boundary is estimated; the distribution of critical currents is obtained, and its peculiarities are explored. It is examined thoroughly how the finite resolution capacity of the cluster geometrical size measurement affects the estimated value of fractal dimension. The effect of fractal properties of the normal phase clusters on the electric field arising from magnetic flux motion is investigated in the case of an exponential distribution of cluster areas. The voltage-current characteristics of superconductors in the resistive state for an arbitrary fractal dimension are obtained. It is revealed that the fractality of the boundaries of the normal phase clusters intensifies the magnetic flux trapping and thereby raises the critical current of a superconductor.Comment: revtex, 16 pages with 1 table and 5 figures; text and figures are improved; more detailed version with geometric probability analisys of the distribution of entry points into weak links over the perimeter of a normal phase clusters and one additional figure is published in Phys.Rev.B; alternative e-mail of author is [email protected]

    Neutrino cross sections at high energies and the future observations of ultrahigh-energy cosmic rays

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    We show that future detectors of ultrahigh-energy cosmic-ray neutrinos will be able to measure neutrino-nucleon cross section at energies as high as 10^{11}GeV or higher. We find that the flux of up-going charged leptons per unit surface area produced by neutrino interactions below the surface is inversely proportional to the cross section. This contrasts with the rate of horizontal air showers (HAS) due to neutrino interactions in the atmosphere, which is proportional to the cross section. Thus, by comparing the HAS and up-going air shower (UAS) rates, the neutrino-nucleon cross section can be inferred. Taken together, up-going and horizontal rates ensure a healthy total event rate, regardless of the value of the cross section.Comment: 4 pages, 2 figures, revtex; final draf

    Dynamics and thermodynamics of axisymmetric flows: I. Theory

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    We develop new variational principles to study stability and equilibrium of axisymmetric flows. We show that there is an infinite number of steady state solutions. We show that these steady states maximize a (non-universal) HH-function. We derive relaxation equations which can be used as numerical algorithm to construct stable stationary solutions of axisymmetric flows. In a second part, we develop a thermodynamical approach to the equilibrium states at some fixed coarse-grained scale. We show that the resulting distribution can be divided in a universal part coming from the conservation of robust invariants and one non-universal determined by the initial conditions through the fragile invariants (for freely evolving systems) or by a prior distribution encoding non-ideal effects such as viscosity, small-scale forcing and dissipation (for forced systems). Finally, we derive a parameterization of inviscid mixing to describe the dynamics of the system at the coarse-grained scale

    Development of Hydrometallurgical Process of Non-Ferrous and Rare Metals Recovery from Untraditional Mineral Raw Materials and Natural Brines

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    In connection with gradual lowering of supplies of tradit- ional ore raw materials involving non-ferrous and rare metals, winch is treated by well-known technologies, invo-lving into the production of untraditional, secondary and technogeneous raw materials appears to be actual task
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