3,046 research outputs found
Evaluation of ignition mechanisms in selected nonmetallic materials
Test program evaluates thermal and electric ignition mechanisms in selected nonmetallic materials found in spacecraft with concentrated oxygen atmospheres. The phenomena evaluated were spontaneous ignition, ignition of flammable vapor by a spark, and ignition by an arc where the arc produces the combustible vapor and the ignition source
Evaluation of ignition mechanisms in selected spacecraft materials Final report, 1 Mar. - 30 Jun. 1967
Evaluation of ignition mechanisms for spacecraft materials in simulated spacecraft cabin atmosphere
Neutrino spin relaxation in medium with stochastic characteristics
The helicity evolution of a neutrino interacting with randomly moving and
polarized matter is studied. We derive the equation for the averaged neutrino
helicity. The type of the neutrino interaction with background fermions is not
fixed. In the particular case of a tau-neutrino interacting with
ultrarelativistic electron-positron plasma we obtain the expression for the
neutrino helicity relaxation rate in the explicit form. We study the neutrino
spin relaxation in the relativistic primordial plasma. Supposing that the
conversion of left-handed neutrinos into right-handed ones is suppressed at the
early stages of the Universe evolution we get the upper limit on the
tau-neutrino mass.Comment: 6 pages, RevTeX4; 2 references added; more detailed discussion of
correlation functions and cosmological neutrinos is presented; version to be
published in Int. J. Mod. Phys.
Minimal distance transformations between links and polymers: Principles and examples
The calculation of Euclidean distance between points is generalized to
one-dimensional objects such as strings or polymers. Necessary and sufficient
conditions for the minimal transformation between two polymer configurations
are derived. Transformations consist of piecewise rotations and translations
subject to Weierstrass-Erdmann corner conditions. Numerous examples are given
for the special cases of one and two links. The transition to a large number of
links is investigated, where the distance converges to the polymer length times
the mean root square distance (MRSD) between polymer configurations, assuming
curvature and non-crossing constraints can be neglected. Applications of this
metric to protein folding are investigated. Potential applications are also
discussed for structural alignment problems such as pharmacophore
identification, and inverse kinematic problems in motor learning and control.Comment: Submitted to J. Phys.:Condens. Matte
Semi-leptonic (1968) decays as a scalar meson probe
The unusual multiplet structures associated with the light spin zero mesons
have recently attracted a good deal of theoretical attention. Here we discuss
some aspects associated with the possibility of getting new experimental
information on this topic from semi-leptonic decays of heavy charged mesons
into an isosinglet scalar or pseudoscalar plus leptons.Comment: 11 pages, 4 figure
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