Genera Zized Variationa I Prhcz $ Zes for Convective Heat Transfer and Irreversz ’ b k Thermodynamics
Variational principles for convective heat transfer are extended to nonhomogeneous fluids and to fluids with thermal expansion. The results apply to nonlinear problems with temperature dependent properties. The context is restricted to heat transfer but the derivation and a discussion of the physics brings out the general validity of the variational principles for a large category of irreversible processes.
A variational principle for convection of heat in anisotropic media
A variational principle for transient convection of heat in incompressible anisotropic media has been developed.
Long Ceramic Beam Tubes for Accelerator Magnets
The ceramic beam tubes for the fast and abort kickers and the bucker and pinger magnets used at Fermilab must meet a number of exacting requirements. The tubes must be long and sufficiently straight so as not to limit magnet design. They must have wall strength capable of withstanding the atmospheric and mechanical forces encountered during construction and operation. Vacuum tight ceramic to stainless steel transitions must be of reasonable cost; they must also withstand high temperature processing and remain vacuum tight to the 10/sup -9/ Torr range. To remove the possibility of static charge buildup each tube must have a surface coating of indium oxide applied to the inner wall. This thin coating is difficult to achieve and requires the most careful attention to detail. The methods used at Fermilab to achieve these goals are presented in this paper.