3 research outputs found
Inflation driven by causal heat flux
We find a simple inflationary solution in an inhomogeneous spacetime with
heat flux. The heat flux obeys a causal transport equation, and counteracts the
inflationary decrease of energy density. At late times, the heat flux tends to
zero and the fluid approaches the equation of state .Comment: Latex 5 pages; to appear Gen. Rel. Gra
Ionospheric anomalies detected by ionosonde and possibly related to crustal earthquakes in Greece
Ionosonde data and crustal earthquakes with magnitude
M > 6:0 observed in Greece during the 2003–2015
period were examined to check if the relationships obtained
earlier between precursory ionospheric anomalies and earthquakes
in Japan and central Italy are also valid for Greek
earthquakes. The ionospheric anomalies are identified on the
observed variations of the sporadic E-layer parameters (h0Es,
foEs) and foF2 at the ionospheric station of Athens. The
corresponding empirical relationships between the seismoionospheric
disturbances and the earthquake magnitude and
the epicentral distance are obtained and found to be similar
to those previously published for other case studies.
The large lead times found for the ionospheric anomalies
occurrence may confirm a rather long earthquake preparation
period. The possibility of using the relationships obtained for
earthquake prediction is finally discussed.Published361–3712A. Fisica dell'alta atmosferaJCR Journa
Thermodynamic classifications and dilatonic black holes
We analyze the thermodynamics of systems which have entropy functions of the type S(m) = am? + b, where m is an extensive variable and a, b, and ? are constants. Such functions apply to dilatonic black holes whose mass is m. This analysis continues our earlier treatment of the general classification of the thermodynamics of systems by whether they exhibit entropy functions which may or may not be either superadditive, homogeneous or concave in the extensive variables on which the entropy depends. This leads to a classification into 8 types of thermodynamics (with several subtypes). We show that only five of these are available for systems having the entropy given above, and these are in fact realized if the constants are given appropriate values