Shale gas - How does it affect the Gas market?

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B-parameters of 4-fermion operators from lattice QCD

This talk summarizes the status of the calculations of $B_K$, $B_7$, $B_8$, and $B_s$, done in collaboration with T. Bhattacharya, G. Kilcup, and S. Sharpe. Results for staggered, Wilson, and Clover fermions are presented.Comment: 3 pages. Package submitted in uufiles format: unpack and latex paper.tex. Talk presented at LATTICE97 (Light Hadron Phenomenology

Electromagnetic Signals and Backgrounds in Heavy-Ion Collisions:

Aspects of the dilepton spectrum in heavy-ion collisions are discussed, with special emphasis on using lattice computations to guide the phenomenology of finite temperature hadronic matter. The background rates for continuum dileptons expected in forthcoming experiments are summarised. Properly augmented by data from ongoing measurements at HERA, these rates will serve as a calibrating background for QGP searches. Recent results on the temperature dependence of the hadronic spectrum obtained in lattice computations below the deconfinement transition are summarised. Light vector meson masses are strongly temperature dependent. Accurate measurements of a resolved $\rho$-peak in dimuon spectra in present experiments are thus of fundamental importance. [file-length=200k characters; instructions for processing given; some Latex versions give error messages: ignore them completely]Comment: 9 pages (incl figures), preprint HLRZ 53/9

Effect of surface hydrogen on the anomalous surface segregation behavior of Cr in Fe-rich Fe-Cr alloys

The segregation behavior of Cr in dilute Fe-Cr alloys is known to be anomalous since the main barrier for surface segregation of Cr in these alloys arises not from the topmost surface layer but from the subsurface layer where the solution energy of Cr is much more endothermic as compared to the topmost surface layer. The Fe-Cr alloys are candidate structural materials for the new generation of nuclear reactors. The surfaces of these alloys will be exposed to hydrogen or its isotopes in these reactors, and although hydrogen is soluble neither in Fe nor in Fe-Cr alloys, it is known that the adsorption energy of hydrogen on the surface of iron is not only exothermic but relatively large. This clearly raises the question of the effect of the hydrogen adsorbed on the surface of iron on the segregation behavior of chromium towards the surface of iron. In this paper we show, on the basis of our ab initio density functional theory calculations, that the presence of hydrogen on the surface of iron leads to a considerably reduced barrier for Cr segregation to both the topmost surface layer and the subsurface layer, but the subsurface layer still controls the barrier for surface segregation. This reduction in the barrier for surface segregation is due to the nature of the Cr-H couple that acts in a complex and synergistic manner. The presence of Cr enhances the exothermic nature of hydrogen adsorption that in turn leads to a reduced barrier for surface segregation. These results should be included in the multiscale modeling of Fe-Cr alloys