Role of Landau-Rabi quantization of electron motion on the crust of magnetars within the nuclear energy density functional theory

Magnetic fields of order $10^{15}$ G have been measured at the surface of some neutron stars, and much stronger magnetic fields are expected to be present in the solid region beneath the surface. The effects of the magnetic field on the equation of state and on the composition of the crust due to Landau-Rabi quantization of electron motion are studied. Both the outer and inner crustal regions are described in a unified and consistent way within the nuclear-energy density functional theory.Comment: 23 pages, 11 figure

Landau quantization and neutron emissions by nuclei in the crust of a magnetar

Magnetars are neutron stars endowed with surface magnetic fields of the order of $10^{14}-10^{15}$~G, and with presumably much stronger fields in their interior. As a result of Landau quantization of electron motion, the neutron-drip transition in the crust of a magnetar is shifted to either higher or lower densities depending on the magnetic field strength. The impact of nuclear uncertainties is explored considering the recent series of Brussels-Montreal microscopic nuclear mass models. All these models are based on the Hartree-Fock-Bogoliubov method with generalized Skyrme functionals. They differ in their predictions for the symmetry energy coefficient at saturation, and for the stiffness of the neutron-matter equation of state. For comparison, we have also considered the very accurate but more phenomenological model of Duflo and Zuker. Although the equilibrium composition of the crust of a magnetar and the onset of neutron emission are found to be model dependent, the quantum oscillations of the threshold density are essentially universal.Comment: 7 pages, 2 figure

Effects of Sowing Date and Phosphorus Fertiliser Application on Winter Survival of Lucerne cv. Aohan in the Northern Semi-Arid Region of China

In the northern semi-arid region of China, winter survival is always a limiting factor for lucerne production, because low temperatures and a dry climate in winter (Zhou et al., 1993; Ma, 2000; Sun & Gui, 2001; Sun et al., 2003). An experiment was conducted to find an appropriate sowing date and P application rate in order to improve lucerne winter survival

Virtual Teamwork Environment -A Web-Based Conical Administration Framework for MNC

Because today\u27s commerce is information intensive and requires sophisticated computer support, it is difficult for the traditional corporations working individually to adapt the new environment to utilize information and build multinational teams effectively and efficiently. The need for global competitiveness makes multinational corporation (MNC) shift to a new team style: virtual teams, which are groups of individuals collaborating in the execution of a specific project while located at multiple individual sites or multiple group sites [1]. The environment of a virtual team is a cyberspace in which virtual project groups communicate mutually. In this paper, we focus on the functionality and structure of this highly abstract system. The groupware available for the teamwork collaboration is briefly introduced. A web-based teamwork environment served for MNC is thenpresented. We present a conical management architecture combined with a network topology: a peers and client/server mode instead of the traditional client/server and pure peers mode. It provides an orderly teamwork environment to replace the crowed and chaos-like teamwork space used currently. A design and implementation of the framework is finally described based on Sun Microsystems\u27 Java languag

Use of computer simulation to establish parameters of steel structure strengthening elements

The article presents the results of computer simulation related to establishing the parameters of mine hoisting machine steel structure strengthening elements. The simulation was performed using the ANSYS computer program. The basis of this program is the finite element method therefore, selecting the type and the size of the finite element affects the calculation accuracy. There have been studied 11 computer models. The results obtained make it possible to establish the strengthening element optimal shape, size and thickness. The most optimal shape of the pad is a disc; this has a positive effect on reducing the level of mechanical stresses in the fracture zone of the beam. The strengthening element «disc pad» is used to combat fatigue failure of the brake beam structures of a mine hoisting machine. The article presents practical experience in the fight against fatigue failure of f mine hoisting machine steel structures