9,493 research outputs found
A Note on Disk Drag Dynamics
The electrical power consumed by typical magnetic hard disk drives (HDD) not
only increases linearly with the number of spindles but, more significantly, it
increases as very fast power-laws of speed (RPM) and diameter. Since the
theoretical basis for this relationship is neither well-known nor readily
accessible in the literature, we show how these exponents arise from
aerodynamic disk drag and discuss their import for green storage capacity
planning.Comment: 5 pages, 3 figure
Decline in extinction rates and scale invariance in the fossil record
We show that the decline in the extinction rate during the Phanerozoic can be
accurately parameterized by a logarithmic fit to the cumulative total
extinction. This implies that extinction intensity is falling off approximately
as the reciprocal of time. We demonstrate that this observation alone is
sufficient to explain the existence of the proposed power-law forms in the
distribution of the sizes of extinction events and in the power spectrum of
Phanerozoic extinction, results which previously have been explained by
appealing to self-organized critical theories of evolutionary dynamics.Comment: 11 pages including 3 postscript figures, typeset in LaTeX 2e using
the Elsevier macro package elsart.cl
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