23,157 research outputs found
Apparatus and method for reducing thermal stress in a turbine rotor
A gas turbine is described wherein the thermal stresses in the turbine rotor are reduced. The rotor includes a central disc with a peripheral rim, and a plurality of blades extending radially outward from the rim. To reduce thermal stresses, a duct arrangement is provided which selectively directs hot gases from the turbine combustor to the rim during the turbine start up. The hot gases from the combustor serve to heat the rim, and decrease the start up period necessary to bring the temperature profile of the rotor into the operating temperature range. After the start up period, the duct arrangement is then used to direct cool gases from the turbine compressor to the rim of the rotor in order to maintain a lower rotor equilibrium temperature
Screening Masses and Improvement in Pure SU(2) Lattice Gauge Theory at High Temperatures
From the long-distance behaviour of gluon and Polyakov loop correlation
functions we extract masses resp. energies in the electric and magnetic
sectors. We discuss their dependence on the temperature and on the momentum as
well as the relevance of an improvement of the lattice discretization of the
action.Comment: Talk presented at LATTICE97 (Finite Temperature and Density) by J.
Rank, 3 pages, LaTeX File, espcrc2.sty Style File and 2 eps figures include
A comparative study of 1959-60 referrals to the school adjustment counselling services of Malden and Needham
Thesis (M.S.)--Boston Universit
Quantum Flux and Reverse Engineering of Quantum Wavefunctions
An interpretation of the probability flux is given, based on a derivation of
its eigenstates and relating them to coherent state projections on a quantum
wavefunction. An extended definition of the flux operator is obtained using
coherent states. We present a "processed Husimi" representation, which makes
decisions using many Husimi projections at each location. The processed Husimi
representation reverse engineers or deconstructs the wavefunction, yielding the
underlying classical ray structure. Our approach makes possible interpreting
the dynamics of systems where the probability flux is uniformly zero or
strongly misleading. The new technique is demonstrated by the calculation of
particle flow maps of the classical dynamics underlying a quantum wavefunction.Comment: Accepted to EP
Real trajectories in the semiclassical coherent state propagator
The semiclassical approximation to the coherent state propagator requires
complex classical trajectories in order to satisfy the associated boundary
conditions, but finding these trajectories in practice is a difficult task that
may compromise the applicability of the approximation. In this work several
approximations to the coherent state propagator are derived that make use only
of real trajectories, which are easier to handle and have a more direct
physical interpretation. It is verified in a particular example that these real
trajectories approximations may have excellent accuracy.Comment: 19 pages, 6 figure
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