Complex research of the unclosed HTS shield for improving homogeneity of the magnetic field

Abstract Homogeneous magnetic fields are required in different applications. The resolution of MRI techniques depends on the quality of the magnetic field, as well as the efficiency of electron cooling systems used at particle accelerators. Unclosed magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. The shield is a lengthwise winding made from YBCO tapes are wound along a carcass generatrix. Then it is positioned coaxially inside an electromagnet. The measurements were carried out under quasistationary conditions, magnetic fields up to 1 kG at 77K. This paper discusses the design of the superconducting shield and presents experimental and numerical studies into the homogeneity of the magnetic field in solenoids with the superconducting shield.</jats:p

Conductivity in Two-Dimensional Disordered Model with Anisotropic Long-Range Hopping

We consider two-dimensional system of particles localized on randomly distributed sites of squared lattice with anisotropic transfer matrix elements between localized sites. By summing of "diffusion ladder" and "cooperon ladder" type vertices we calculated the conductivity for various sites and particles densities.Comment: Latex, 10 page

Determination of the preliminary phase of the facility destruction based on the resistance-acoustic method of control

The article substantiates the use of the resistance-acoustic method in problems of non-destructive testing of mechanical stresses or defects in structures of metals and alloys in natural and technical systems. The possibilities of the use of the proposed method for the potential monitored facilities were analyzed, to which the strict requirements for operational security are imposed (bearing reinforced concrete structures, bridges, radio and television towers, etc.

On the Possible Enhancement of the Magnetic Field by Neutrino Reemission Processes in the Mantle of a Supernova

URCA neutrino reemission processes under the conditions in the mantle of a supernova with a strong toroidal magnetic field are investigated. It is shown that parity violation in these processes can be manifested macroscopically as a torque that rapidly spins up the region of the mantle occupied by such a field. Neutrino spin-up of the mantle can strongly affect the mechanism of further generation of the toroidal field, specifically, it can enhance the field in a small neighborhood of the rigid-body-rotating core of the supernova remnant.Comment: 8 pages, late

Neutrino Emission from Magnetized Proto-Neutron Stars in Relativistic Mean Field Theory

We make a perturbative calculation of neutrino scattering and absorption in hot and dense hyperonic neutron-star matter in the presence of a strong magnetic field. We find that the absorption cross-sections show a remarkable angular dependence in that the neutrino absorption strength is reduced in a direction parallel to the magnetic field and enhanced in the opposite direction. This asymmetry in the neutrino absorbtion can be as much as 2.2 % of the entire neutrino momentum for an interior magnetic field of \sim 2 x 10^{17} G. We estimate the pulsar kick velocities associated with this asymmetry in a fully relativistic mean-field theory formulation. We show that the kick velocities calculated here are comparable to observed pulsar velocities.Comment: arXiv admin note: substantial text overlap with arXiv:1009.097

Predicting the non-breeding distributions of the two Asian subspecies of Black-tailed Godwit using morphological information

Until recently, Limosa limosa melanuroides was thought to be the only subspecies of Black-tailed Godwit in the East Asian–Australasian Flyway. For this reason, all previous occurrences and counts of Black-tailed Godwits in the flyway have been assigned to melanuroides. However, a larger-bodied subspecies, bohaii, has recently been discovered in the flyway. As a result, the occurrence of Black-tailed Godwits in the flyway needs to be reconsidered such that the specific distribution of each subspecies becomes known. To this end, we developed a simple discriminant function to assign individuals to subspecies based on their bill and wing length. Cross-validation with individuals known to be bohaii or melanuroides, based on molecular analysis, showed the developed function to be 97.7% accurate. When applied to measurements of godwits captured at 22 sites across 9 countries in East–Southeast Asia and Australia, we found that bohaii and melanuroides occurred at most sites and overlapped in their distribution from Kamchatka to Australia. We examined photos from all along the flyway to verify this surprising result, confirming that both subspecies co-occur in most locations. Based on these results, we hypothesise that bohaii and melanuroides from the west of their breeding ranges mostly migrate over Chinese mainland. Birds of both subspecies from the east of their ranges are expected to migrate along the Pacific Ocean. We encourage ringing groups in East–Southeast Asia and Australia to use this simple method to keep adding knowledge about Black-tailed Godwits in the East Asian–Australasian Flyway

Pulsar kicks from neutrino oscillations

Neutrino oscillations in a core-collapse supernova may be responsible for the observed rapid motions of pulsars. Given the present bounds on the neutrino masses, the pulsar kicks require a sterile neutrino with mass 2-20 keV and a small mixing with active neutrinos. The same particle can be the cosmological dark matter. Its existence can be confirmed the by the X-ray telescopes if they detect a 1-10 keV photon line from the decays of the relic sterile neutrinos. In addition, one may be able to detect gravity waves from a pulsar being accelerated by neutrinos in the event of a nearby supernova.Comment: invited review article to appear in Int. J. Mod. Phys. (21 pages, 6 figures

Complex research of the unclosed HTS shield for improving homogeneity of the magnetic field

Abstract Homogeneous magnetic fields are required in different applications. The resolution of MRI techniques depends on the quality of the magnetic field, as well as the efficiency of electron cooling systems used at particle accelerators. Unclosed magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. The shield is a lengthwise winding made from YBCO tapes are wound along a carcass generatrix. Then it is positioned coaxially inside an electromagnet. The measurements were carried out under quasistationary conditions, magnetic fields up to 1 kG at 77K. This paper discusses the design of the superconducting shield and presents experimental and numerical studies into the homogeneity of the magnetic field in solenoids with the superconducting shield.</jats:p