291,588 research outputs found
Pressure deformation of tires using differential stiffness for triangular solid-of-revolution elements
The derivation is presented of the differential stiffness for triangular solid of revolution elements. The derivation takes into account the element rigid body rotation only, the rotation being about the circumferential axis. Internal pressurization of a pneumatic tire is used to illustrate the application of this feature
Searching for radiative pumping lines of OH masers: II. The 53.3um absorption line towards 1612MHz OH maser sources
This paper analyzes the 53.3um line in the ISO LWS spectra towards a similar
sample of OH/IR sources. We find 137 LWS spectra covering 53.3um and associated
with 47 galactic OH/IR sources. Ten of these galactic OH/IR sources are found
to show and another 5 ones tentatively show the 53.3um absorption while another
7 sources highly probably do not show this line. The source class is found to
be correlated with the type of spectral profile: red supergiants (RSGs) and AGB
stars tend to show strong blue-shifted filling emission in their 53.3um
absorption line profiles while HII regions tend to show a weak red-shifted
filling emission in the line profile. GC sources and megamasers do not show
filling emission feature. It is argued that the filling emission might be the
manifestation of an unresolved half emission half absorption profile of the
53.3um doublet. The 53.3 to 34.6um equivalent width (EW) ratio is close to
unity for RSGs but much larger than unity for GC sources and megamasers while H
II regions only show the 53.3um line. The pump rate defined as maser to IR
photon flux ratio is approximately 5% for RSGs. The pump rates of GC sources
are three order of magnitude smaller. Both the large 53.3 to 34.6um EW ratio
and the small pump rate of the GC OH masers reflect that the two detected
`pumping lines' in these sources are actually of interstellar origin. The pump
rate of Arp 220 is 32%--much larger than that of RSGs, which indicates that the
contribution of other pumping mechanisms to this megamaser is important.Comment: 34 pages, 12 figures, 4 table
Non-exponential kinetic behavior of confined water
We present the results of molecular dynamics simulations of SPC/E water
confined in a realistic model of a silica pore. The single-particle dynamics
have been studied at ambient temperature for different hydration levels. The
confinement near the hydrophilic surface makes the dynamic behaviour of the
liquid strongly dependent on the hydration level. Upon decrease of the number
of water molecules in the pore we observe the onset of a slow dynamics due to
the ``cage effect''. The conventional picture of a stochastic single-particle
diffusion process thus looses its validity
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