The condition for the existence of the superradiance modes is derived for the incident scalar, electromagnetic and gravitational waves when the spacetime background is a higher-dimensional rotating black hole with multiple angular momentum parameters. The final expression of the condition is 0 < ω < ∑ i miΩi, where Ωi is an angular frequency of the black hole and, ω and mi are the energy of the...

Where are the r-modes of isentropic stars? ABSTRACT Almost none of the r-modes ordinarily found in rotating stars exist, if the star and its perturbations obey the same one-parameter equation of state; and rotating relativistic stars with one-parameter equations of state have no pure r-modes at all, no modes whose limit, for a star with zero angular velocity, is a perturbation with axial parity...

Connectedness and applied stress strongly affect elasticity in solids. In various amorphous materials, mechanical stability can be lost either by reducing connectedness or by increasing pressure. We present an effective medium theory of elasticity that extends previous approaches by incorporating the effect of compression, of amplitude e, allowing one to describe quantitative features of sound ...

Introduction Star trackers are increasingly used on modern day spacecraft. With the rapid advancement of imaging hardware and high-speed computer processors, current trackers are small and routinely achieve arc-second attitude accuracy. Typical sampling rates for these trackers range from 1 to 10 Hz. As computer processor technology advances these frequencies will increase, leading to filter de...

where ρdos(ν) is the density of states of phonons at frequency ν and other parameters are explained in the original paper. The values of γr used in the paper were based on the experimental results. Therefore, the error in Eq. (A26) does not affect any conclusions and results of the paper. The derivation of this expression follows Carmichael (Ref. 1, Chap. 1.3). Starting with the equations for c...

Carnot established in 1824 that the efficiency of cyclic engines operating between a hot bath at absolute temperature Thot and a cold bath at temperature Tcold cannot exceed 1−Tcold/Thot. This result implies the existence of an entropy function S(U) with the property that dS/dU ≤ 0, where U denotes the average energy. Linear singlemode systems alternately in contact with hot and cold baths obey...

Mercury-supported, self-assembled monolayers (SAMs) of the sole dioleoylphosphatidylcholine (DOPC) and of a raft-forming mixture of DOPC, cholesterol (Chol) and palmitoylsphingomyelin (PSM) of (59:26:15) mol% composition, were investigated by electrochemical impedance spectroscopy (EIS), both in the absence and in the presence of the monosialoganglioside GM1. The impedance spectra of these four...

Particle motion is considered in incompressible two-dimensional flows consisting of a steady background gyre on which an unsteady wave-like perturbation is superimposed. A dynamical systems point of view that exploits the action-angle formalism is adopted. It is argued and demonstrated numerically that for a large class of problems one expects to observe a mixed phase space, i.e. the occurrence...

on 11th of august 2012 the region was surprisingly struck by a shallow mw 6.4 (usgs) earthquake with pure right-lateral strike-slip character only about 50 km north of the north-tabriz fault. an east-west striking surface rupture of about 20 km length was observed in the field by geological survey of iran. only 11 minutes later and about 6 km further nw a second shallow event with mw 6.2 occurr...

We consider the dynamics of networks of oscillators that are weakly dissipative perturbations of identical Hamiltonian oscillators with weak coupling. Suppose the Hamiltonian oscillators have angular frequency ω(α) when their energy is α. We address the problem of what happens in a neighbourhood of where dω/dα = 0; we refer to this as a point of isochronicity for the oscillators. If the couplin...