Aspects of Boundary Conditions for Nonabelian Gauge Theories

The boundary values of the time-component of the gauge potential form externally specifiable data characterizing a gauge theory. We point out some consequences such as reduced symmetries, bulk currents for manifolds with disjoint boundaries and some nuances of how the charge algebra is realized.Comment: 15 page

Relativistic Green functions in a plane wave gravitational background

We consider a massive relativistic particle in the background of a gravitational plane wave. The corresponding Green functions for both spinless and spin 1/2 cases, previously computed by A. Barducci and R. Giachetti \cite{Barducci3}, are reobtained here by alternative methods, as for example, the Fock-Schwinger proper-time method and the algebraic method. In analogy to the electromagnetic case, we show that for a gravitational plane wave background a semiclassical approach is also sufficient to provide the exact result, though the lagrangian involved is far from being a quadratic one.Comment: Last paper by Professor Arvind Narayan Vaidya, 18 pages, no figure

No news for Kerr-Schild fields

Algebraically special fields with no gravitational radiation are described. Kerr-Schild fields, which include as a concrete case the Kinnersley photon rocket, form an important subclass of them.Comment: 4 pages, Revtex

Some experiences in Electro-winning of Aluminium from fused Chloride bath

ALTHOUGH the electro-winning of aluminium from a fused chloride bath dates back to 1854, when Bunsen first isolated the metal, the interest in the process since then has been sporadic. Some of the earlier documenters like Mellor', Richards2, Borches3 and others had taken up the lead, but had been discouraged into branding the approach as impracticable. Patents filed by Aluminium Industrie A.G.4, I.G. Farben Industrie, A.G.5, Henriques and Thomsen6, Brode7, Treadwell8, Daudonnet9 and others during the period 1928 to 1931 indicated a resurgence of the chloride bath, although in the subsequent period the only mentionable patents were by Lovel and Phillips in 194510, Electronic Reduction Corporation in 1951,11 Grothe12 in 1953, and by Slatin13 in 1959 and 1963. Some of these were for the declared purpose of electroplating rather than electro-winning. The published investigations are also equally sporadic, and mention may be made of the work of Fink and Solanki14, Ramachandran15, and Newalkar and Altekar16

Flow Transients in Supercritical CO2 Natural Circulation Loop

AbstractA one-dimensional transient code is developed for studying the flow transient in the supercritical CO2 natural circulation loop. The transient code is validated with the experimental result. Various flow transients such as flow initiation, power step up and power step back have been studied. The effect of operational parameters and geometrical parameters on flow initiation transient also has been studied. In all cases steady state has been reached and instability is not observed in vertical heater vertical cooler configuration of supercritical CO2 natural circulation loop