8,944 research outputs found
Calculating the Parameters of an Inductive Short Circuit Current Limiter with a Superconducting Shield
An inductive short circuit current limiter with a superconducting shield and its operation under normal and emergency conditions are analyzed. A method for calculating its key parameters is proposed
Poisson's ratio in cryocrystals under pressure
We present results of lattice dynamics calculations of Poisson's ratio (PR)
for solid hydrogen and rare gas solids (He, Ne, Ar, Kr and Xe) under pressure.
Using two complementary approaches - the semi-empirical many-body calculations
and the first-principle density-functional theory calculations we found three
different types of pressure dependencies of PR. While for solid helium PR
monotonically decreases with rising pressure, for Ar, Kr, and Xe it
monotonically increases with pressure. For solid hydrogen and Ne the pressure
dependencies of PR are non-monotonic displaying rather deep minimums. The role
of the intermolecular potentials in this diversity of patterns is discussed.Comment: Fizika Nizkikh Temperatur 41, 571 (2015
Benchmark on neutron capture extracted from reactions
Direct neutron capture reactions play an important role in nuclear
astrophysics and applied physics. Since for most unstable short-lived nuclei it
is not possible to measure the cross sections, reactions
have been used as an alternative indirect tool. We analyze simultaneously
at deuteron energies and 56 MeV
and the thermal reaction at 25 meV. We include results for the
ground state and the first excited state of Ca. From the low-energy
reaction, the neutron asymptotic normalization coefficient (ANC) is
determined. Using this ANC, we extract the spectroscopic factor (SF) from the
higher energy data and the data. The SF obtained through
the 56 MeV data are less accurate but consistent with those from the
thermal capture. We show that to have a similar dependence on the single
particle parameters as in the , the (d,p) reaction should be
measured at 30 MeV.Comment: 5 pg, 4 figs, Phys. Rev. C (rapid) in pres
Primordial magnetic fields and nonlinear electrodynamics
The creation of large scale magnetic fields is studied in an inflationary
universe where electrodynamics is assumed to be nonlinear. After inflation ends
electrodynamics becomes linear and thus the description of reheating and the
subsequent radiation dominated stage are unaltered. The nonlinear regime of
electrodynamics is described by lagrangians having a power law dependence on
one of the invariants of the electromagnetic field. It is found that there is a
range of parameters for which primordial magnetic fields of cosmologically
interesting strengths can be created.Comment: 21 pages, 3 figure
Primordial black holes and asteroid danger
Probability for a primordial black hole to invade the Kuiper belt was
calculated. We showed that primordial black holes of certain masses can
significantly change asteroids' orbits. These events may result in disasters,
local for our solar system and global for the Earth (like the Tunguska
meteorite). We also estimated how often such events occur.Comment: 5 page
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