257 research outputs found
Self-oscillations in an Alpha Stirling Engine: a bifurcation analysis
We study a thermo-mechanical system comprised of an alpha Stirling engine and
a flywheel from the perspective of dynamical systems theory. Thermodynamics
establish a static relation between the flywheel's angle and the forces exerted
by the two power pistons that constitute the engine. Mechanics, in turn,
provide a dynamic relation between the forces and the angle, ultimately leading
to a closed dynamical model. We are interested in the different behaviors that
the engine displays as parameters are varied. The temperature of the hot piston
and the mechanical phase between both pistons constitute our bifurcation
parameters. Considering that energy conversion in the engine can only take
place through cyclic motions, we are particularly interested in the appearance
of limit cycles.Comment: To be submitte
Symmetry algebra of a generalized anisotropic harmonic oscillator
It is shown that the symmetry Lie algebra of a quantum system with accidental degeneracy can be obtained by means of the Noether's theorem. The procedure is illustrated by considering a generalized anisotropic two dimensional harmonic oscillator, which can have an infinite set of states with the same energy characterized by an u(1,1) Lie algebra
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