15,438 research outputs found
The strengthening of reentrant pinning by collective interactions in the peak effect
Since it was first observed about 40 years ago [1], the peak effect has been
the subject of numerous research mainly impelled by the desire to determine its
exact mechanisms. Despite these efforts, a consensus on this question has yet
to be reached. Experimentally, the peak effect indicates a transition from a
depinned vortex phase to a reentrant pinning phase at high magnetic field. To
study the effects of intrinsic pinning on the peak effect, we consider
FeNiZr superconducting metallic glasses in which the vortex
pinning force varies depending on the Fe content and in which a huge peak
effect is seen as a function of magnetic field. The results are mapped out as a
phase diagram in which it is readily seen that the peak effect becomes broader
with decreasing pinning force. Typically, pinning can be understood by
increased pinning centers, but here, we show that reentrant pinning is due to
the strengthening of interactions (while decreasing pinning strength). Our
results demonstrate the strengthening of the peak effect by collective effects.Comment: 4 pages, 4 figure
Atomization of broad specification aircraft fuels
The atomization properties of liquid fuels for the potential use in aircraft gas turbine engines are discussed. The significance of these properties are addressed with respect to the ignition and subsequent combustion behavior of the fuel spray/air mixture. It is shown that the fuel properties which affect the atomization behavior (viscosity, surface tension, and density) are less favorable for the broad specification fuels as compared to with those for conventional fuels
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