A Bohr's Semiclassical Model of the Black Hole Thermodynamics

We propose a simple procedure for evaluating the main thermodynamical attributes of a Schwarzschild's black hole: Bekenstein-Hawking entropy, Hawking's temperature and Bekenstein's quantization of the surface area. We make use of the condition that the circumference of a great circle on the black hole horizon contains finite number of the corresponding reduced Compton's wavelength. It is essentially analogous to Bohr's quantization postulate in Bohr's atomic model interpreted by de Broglie's relation. We present black hole radiation in the form conceptually analogous to Bohr's postulate on the photon emission by discrete quantum jump of the electron within the Old quantum theory. It enables us, in accordance with Heisenberg's uncertainty relation and Bohr's correspondence principle, to make a rough estimate of the time interval for black hole evaporation, which turns out very close to time interval predicted by the standard Hawking's theory. Our calculations confirm Bekenstein's semiclassical result for the energy quantization, in variance with Frasca's (2005) calculations. Finally we speculate about the possible source-energy distribution within the black hole horizon.Comment: no figure

Timing and mechanism of the rise of the Shillong Plateau in the Himalayan foreland

The Shillong Plateau (northeastern India) constitutes the only significant topography in the Himalayan foreland. Knowledge of its surface uplift history is key to understanding topographic development and unraveling tectonic–climate–topographic coupling in the eastern Himalaya. We use the sedimentary record of the Himalayan foreland basin north of the Shillong Plateau to show that the paleo-Brahmaputra river was redirected north and west by the rising plateau at 5.2–4.9 Ma. We suggest that onset of plateau uplift is a result of increased fault-slip rates in response to stresses caused by the Indian lithosphere bending beneath the Himalaya

Electron Impact Ionization Close to the Threshold: Classical Calculations

In this paper we present Classical Trajectory Monte Carlo (CTMC) calculations for single and multiple electron ionization of Argon atoms and ions in the threshold region. We are able to recover the Wannier exponents a for the power-law behavior of the cross section s versus excess energy: the exact value of the exponent as well as the existence of its saturation for multiple ionization appear to be related to how the total binding energy is shared between target electrons.Comment: 9 pages. To be published in Journal of Physics