23,378 research outputs found
On the Second Fundamental Theorem of Asset Pricing
Let be sigma-martingales on . We show
that every bounded martingale (with respect to the underlying filtration)
admits an integral representation w.r.t. if and only if there
is no equivalent probability measure (other than ) under which
are sigma-martingales.
From this we deduce the second fundamental theorem of asset pricing- that
completeness of a market is equivalent to uniqueness of Equivalent
Sigma-Martingale Measure (ESMM)
Initial stages of cavitation damage and erosion on copper and brass tested in a rotating disk device
In view of the differences in flow and experimental conditions, there has been a continuing debate as to whether or not the ultrasonic method of producing cavitation damage is similar to the damage occurring in cavitating flow systems, namely, venturi and rotating disk devices. In this paper, the progress of cavitation damage during incubation periods on polycrystalline copper and brass tested in a rotating disk device is presented. The results indicate several similarities and differences in the damage mechanism encountered in a rotating disk device (which simulates field rotary devices) and a magnetostriction apparatus. The macroscopic erosion appears similar to that in the vibratory device except for nonuniform erosion and apparent plastic flow during the initial damage phase
Size scale effect in cavitation erosion
An overview and data analyses pertaining to cavitation erosion size scale effects are presented. The exponents n in the power law relationship are found to vary from 1.7 to 4.9 for venturi and rotating disk devices supporting the values reported in the literature. Suggestions for future studies were made to arrive at further true scale effects
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