8,518 research outputs found
Equation of State for Water in the Small Compressibility Region
The equation of state for dense fluids has been derived within the framework
of the Sutherland and Katz potential models. The equation quantitatively agrees
with experimental data on the isothermal compression of water under
extrapolation into the high pressure region. It establishes an explicit
relationship between the thermodynamic experimental data and the effective
parameters of the molecular potential
Thermal Radiation from Neutron Stars: Chandra Results
The outstanding capabilities of the Chandra X-ray observatory have greatly
increased our potential to observe and analyze thermal radiation from the
surfaces of neutron stars (NSs). Such observations allow one to measure the
surface temperatures and confront them with the predictions of the NS cooling
models. Detection of gravitationally redshifted spectral lines can yield the NS
mass-to-radius ratio. In rare cases when the distance is known, one can measure
the NS radius, which is particularly important to constrain the equation of
state of the superdense matter in the NS interiors. Finally, one can infer the
chemical composition of the NS surface layers, which provides information about
formation of NSs and their interaction with the environment. We overview the
recent Chandra results on the thermal radiation from various types of NSs --
active pulsars, young radio-quiet neutron stars in supernova remnants, old
radio-silent ``dim'' neutron stars -- and discuss their implications.Comment: URL changed for Figures 1, 12 and 18:
ftp://ftp.xray.mpe.mpg.de/people/zavli
Modeling of "groove" rolling defect on internal surface of pipes at lengthwise rolling
The research has been conducted in pipe forming at rolling off by lengthwise rolling mill with stub mandrel; the patterns of change in dimensionless parameters were determined, which characterize deformation in side angle depending on http://www.multitran.ru/c/m.exe?t=424995_2_1elongation ratio. The model of formation of lengthwise groove on internal surface of pipes has been proposed
Space-Time Description of Scalar Particle Creation by a Homogeneous Isotropic Gravitational Field
We give the generalization of the method of the space-time description of
particle creation by a gravitational field for a scalar field with nonconformal
coupling to the curvature. The space-time correlation function is obtained for
a created pair of the quasi-particles, corresponding to a diagonal form of the
instantaneous Hamiltonian. The case of an adiabatic change of the metric of
homogeneous isotropic space is analyzed. We show that the created pairs of
quasi-particles in de Sitter space should be interpreted as pairs of virtual
particles.Comment: 7 pages, 3 figure
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