We review some of the uncertainties in calculating nucleosynthetic yields, focusing on the explosion mechanism. Current yield calculations tend to either use a piston, energy injection, or enhancement of neutrino opacities to drive an explosion. We show that the energy injection, or more accurately, an entropy injection mechanism is best-suited to mimic our current understanding of the convection-enhanced supernova engine. The enhanced neutrino-opacity technique is in qualitative disagreement with simulations of core-collapse supernovae and will likely produce errors in the yields. But piston-driven explosions are the most discrepant. Piston-driven explosion severely underestimate the amount of fallback, leading to order-of-magnitude errors in the yields of heavy elements. To obtain yields accurate to the factor of a few level, we must use entropy or energy injection and this has become the NuGrid collaboration approach. PoS(NIC X)101 10th Symposium on Nuclei in the Cosmos

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.3.2, section 5.5 and section 7.6. Some of this material has been adopted from various reviews, particularly Christensen-Dalsgaard & Berthomieu (1991). Also, the equation numbering has been revised. It is quite plausible that additional errors have crept in during this revision; as always, I should be most

convectively stable and unstable regions is dynamic and nonspherical, so that the nonturbulent material is driven into motion, even in the absence of “penetrative overshoot. ” These motions may be described by the theory of nonspherical stellar pulsations, and are related to motion measured by helioseismology

Direct evidence for a supernova interacting with a large amount of hydrogen-free circum-stellar material.

sequence. Given these assumptions, the accretion of metal rich material onto the surface of a star during and shortly after the formation of planetary systems should be evident via the enhanced metallicity of the star. Building on previous work, stellar evolution models which include the effects of stellar

of supersonic nature. Methods. We have performed numerical 2-dimensional simulations of jets, with cylindrical and planar (slab) symmetry, crossing the stellar wind material. From the results of the simulations, we derive estimates of the particle acceleration efficiency, using first order Fermi acceleration

is assumed to arise both from the quiescent star and accretion shocks at the base of stellar magnetospheric columns, along which material from the disk accretes. The accretion flux is calculated self-consistently from the accretion mass loss rate. We find that the disk cannot be entirely removed using only

Beside quasi-stationary plasma operation, short tran-sient thermal pulses with deposited energy densities on the order of several tens of MJ/m2 are a serious concern for next-step devices, in particular, for tokamak devices such as ITER. The most serious of these transient events are plasma disruptions. Here, a considerable fraction of the plasma energy is deposited on a localized surface area in the divertor strike zone region. The timescale of these events is typically on the order of 1 ms. In spite of the fact that a dense cloud of ablation vapor will form above the strike zone, only partial shielding of the diver-tor armor from incident plasma particles will occur. As a consequence, thermal shock–induced crack formation, vaporization, surface melting, melt layer ejection, and particle emission induced by brittle destruction pro-

We combine several surveys at different wavelenghts with intermediate-band uvbyβ pho-tometry to examine the correlation between the location of the OB-stars in the Centaurus star-forming field and the neutral and ionized material in GSH 305+01−24 supershell seen in the same direction. Based