Superfluid hydrodynamics in rotating neutron stars. I - Nondissipative equations. II - Dissipative effects

1991 ◽  
Vol 380 ◽  
pp. 515 ◽  
Author(s):  
Gregory Mendell
Keyword(s):  
Neutron Stars ◽  
Dissipative Effects ◽  
Superfluid Hydrodynamics

scholarly journals Stability and gravitational collapse of neutron stars with realistic equations of state

2020 ◽  
Vol 495 (4) ◽  
pp. 5027-5039 ◽  
Author(s):  
J M Z Pretel ◽  
M F A da Silva
Keyword(s):  
Neutron Stars ◽  
Gravitational Collapse ◽  
Numerical Solutions ◽  
Equations Of State ◽  
A Priori ◽  
Energy Conditions ◽  
Complete Analysis ◽  
Dissipative Effects ◽  
The Stability ◽  
The Moment

ABSTRACT We discuss the stability and construct dynamical configurations describing the gravitational collapse of unstable neutron stars with realistic equations of state compatible with the recent LIGO–Virgo constraints. Unlike other works that consider the collapse of a stellar configuration without a priori knowledge if it is stable or unstable, we first perform a complete analysis on stellar stability for such equations of state. Negative values of the squared frequency of the fundamental mode indicate us radial instability with respect to the collapse of the unstable star to a black hole. We find numerical solutions corresponding to the temporal and radial behaviour during the evolution of the collapse for certain relevant physical quantities such as mass, luminosity, energy density, pressure, heat flow, temperature, and quantities that describe bulk viscous processes. Our results show that the equation of state undergoes abrupt changes close to the moment of event horizon formation as a consequence of dissipative effects. During the collapse process all energy conditions are respected, which implies that our model is physically acceptable.

scholarly journals Collective modes in the superfluid inner crust of neutron stars

2015 ◽  
Vol 24 (09) ◽  
pp. 1541006 ◽  
Author(s):  
Michael Urban ◽  
Micaela Oertel
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Transport Properties ◽  
Low Energy ◽  
Collective Modes ◽  
Crystalline Phases ◽  
Long Wavelength ◽  
Thermodynamic And Transport Properties ◽  
Superfluid Hydrodynamics ◽  
Improved Model

The neutron star inner crust is assumed to be superfluid at relevant temperatures. The contribution of neutron quasiparticles to thermodynamic and transport properties of the crust is therefore strongly suppressed by the pairing gap. Nevertheless, the neutron gas still has low-energy excitations, namely long-wavelength collective modes. We summarize different approaches to describe the collective modes in the crystalline phases of the inner crust and present an improved model for the description of the collective modes in the pasta phases within superfluid hydrodynamics.

DISSIPATIVE EFFECTS IN PROJECTILE FRAGMENTATION AND PARTICLES EVAPORATION

1987 ◽  
Vol 48 (C2) ◽  
pp. C2-175-C2-178
Author(s):  
A. BONASERA ◽  
M. DI TORO ◽  
C. GREGOIRE
Keyword(s):  
Projectile Fragmentation ◽  
Dissipative Effects

Neutron Stars and "Black Holes"

1973 ◽  
Vol 110 (7) ◽  
pp. 441 ◽  
Author(s):  
Ya.B. Zel'dovich
Keyword(s):  
Black Holes ◽  
Neutron Stars

Cooling of neutron stars and superfluidity in their cores

1999 ◽  
Vol 169 (8) ◽  
pp. 825 ◽  
Author(s):  
Dmitrii G. Yakovlev ◽  
Kseniya P. Levenfish ◽  
Yurii A. Shibanov
Keyword(s):  
Neutron Stars

Fatigue Investigation of Elastomeric Structures

2010 ◽  
Vol 38 (3) ◽  
pp. 194-212 ◽  
Author(s):  
Bastian Näser ◽  
Michael Kaliske ◽  
Will V. Mars
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Material Behavior ◽  
Period Effect ◽  
Numerical Representation ◽  
Material Force ◽  
Strain Behavior ◽  
Dissipative Effects ◽  
Elastomeric Materials

Abstract Fatigue crack growth can occur in elastomeric structures whenever cyclic loading is applied. In order to design robust products, sensitivity to fatigue crack growth must be investigated and minimized. The task has two basic components: (1) to define the material behavior through measurements showing how the crack growth rate depends on conditions that drive the crack, and (2) to compute the conditions experienced by the crack. Important features relevant to the analysis of structures include time-dependent aspects of rubber’s stress-strain behavior (as recently demonstrated via the dwell period effect observed by Harbour et al.), and strain induced crystallization. For the numerical representation, classical fracture mechanical concepts are reviewed and the novel material force approach is introduced. With the material force approach at hand, even dissipative effects of elastomeric materials can be investigated. These complex properties of fatigue crack behavior are illustrated in the context of tire durability simulations as an important field of application.

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