Instability of Quark Matter Core in a Compact Newborn Neutron Star With Moderately Strong Magnetic Field

It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with moderately strong magnetic field strength, which populates only the electron's Landau levels, then in the $\beta$-equilibrium condition, the quark core is energetically much more unstable than the neutron matter of identical physical condition.Comment: Six pages REVTEX file, one .eps file (included

Neutron star cooling after deep crustal heating in the X-ray transient KS 1731-260

We simulate the cooling of the neutron star in the X-ray transient KS 1731-260 after the source returned to quiescence in 2001 from a long (>~ 12.5 yr) outburst state. We show that the cooling can be explained assuming that the crust underwent deep heating during the outburst stage. In our best theoretical scenario the neutron star has no enhanced neutrino emission in the core, and its crust is thin, superfluid, and has the normal thermal conductivity. The thermal afterburst crust-core relaxation in the star may be not over.Comment: 5 pages, 2 figures, accepted by MNRAS. In v.2, two references added and typos correcte

Thermal X-Ray Pulses Resulting From Pulsar Glitches

The non-spherically symmetric transport equations and exact thermal evolution model are used to calculate the transient thermal response to pulsars. The three possible ways of energy release originated from glitches, namely the `shell', `ring' and `spot' cases are compared. The X-ray light curves resulting from the thermal response to the glitches are calculated. Only the `spot' case and the `ring' case are considered because the `shell' case does not produce significant modulative X-rays. The magnetic field ($\vec B$) effect, the relativistic light bending effect and the rotational effect on the photons being emitted in a finite region are considered. Various sets of parameters result in different evolution patterns of light curves. We find that this modulated thermal X-ray radiation resulting from glitches may provide some useful constraints on glitch models.Comment: 48 pages, 20 figures, submitted to Ap

Increase quality welded joints pipe when using flux cored wire

The article presents a mathematical model of nonlinear thermal processes when multiarc welding of electric welded pipes, allowing to assess changes in the structure of the welded joint obtained using flux cored wire. An experimental study of the influence of various alloying elements of the mechanical properties of the weld metal. Tested microalloying welds through flux cored wire, located on the same arc when welding in multi. According to the results of the study concluded that the efficiency of flux cored wire for welding high strength steel pipe for microalloying of the weld and reducing heat input welding.Представлена математическая модель нелинейных тепловых процессов при многодуговой сварке электросварных труб, позволяющая проводить оценку изменения структуры сварного соединения, полученного при использовании порошковых проволок. Проведено экспериментальное исследование влияния различных легирующих элементов на механические свойства металла шва. Опробовано микролегирование сварных швов через порошковую проволоку, расположенную на одной дуге при многодуговой сварке. По результатам проведенного исследования сделан вывод об эффективности применения порошковой проволоки при сварке высокопрочных трубных сталей для микролегирования сварного шва и снижения погонной энергии сварки

Neutrino emission in neutron matter from magnetic moment interactions

Neutrino emission drives neutron star cooling for the first several hundreds of years after its birth. Given the low energy ($\sim$ keV) nature of this process, one expects very few nonstandard particle physics contributions which could affect this rate. Requiring that any new physics contributions involve light degrees of freedom, one of the likely candidates which can affect the cooling process would be a nonzero magnetic moment for the neutrino. To illustrate, we compute the emission rate for neutrino pair bremsstrahlung in neutron-neutron scattering through photon-neutrino magnetic moment coupling. We also present analogous differential rates for neutrino scattering off nucleons and electrons that determine neutrino opacities in supernovae. Employing current upper bounds from collider experiments on the tau magnetic moment, we find that the neutrino emission rate can exceed the rate through neutral current electroweak interaction by a factor two, signalling the importance of new particle physics input to a standard calculation of relevance to neutron star cooling. However, astrophysical bounds on the neutrino magnetic moment imply smaller effects.Comment: 9 pages, 1 figur