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We study the effects of recently calculated baryon diffusion coefficients on the yields of primordial light elements in baryon-inhomogeneous big-bang models. The new coefficients are an improvement over previously used values in that they go to the correct nonrelativistic limit for neutron-electron scattering and give a more correct numerical value for the nucleon-nucleon scattering contribution. The largest effect of these new coefficients on nucleosynthesis is through neutron-proton scattering. We find that the somewhat larger value for Dnp in the present work shifts the optimum separation distance between fluctuations, at which the effects of inhomogeneities are maximized, to slightly larger distance scales. Otherwise, the nucleosynthesis yields derived using these new diffusion coefficients are similar to those obtained previously thereby confirming the robustness of earlier derived constraints.

It is often useful to simulate radiographic images in order to optimize imaging trade-offs and to test tomographic techniques. HADES is a code that simulates radiography using ray tracing techniques. Although originally developed to simulate X-ray transmission radiography, HADES has grown to simulate neutron radiography over a wide range of energy, proton radiography in the 1 MeV to 100 GeV range, and recently phase contrast radiography using X-rays in the keV energy range. HADES can simulate parallel-ray or cone-beam radiography through a variety of mesh types, as well as through collections of geometric objects. HADES was originally developed for nondestructive evaluation (NDE) applications, but could be a useful tool for simulation of portal imaging, proton therapy imaging, and synchrotron studies of tissue. In this paper we describe HADES' current capabilities and discuss plans for a major revision of the code.

In the study of nucleosynthesis in type II SN, shock waves are initiated artificially, since collapse calculations do not, as yet, give self-consistent shock waves strong enough to produce the SN explosion. The two initiation methods currently used by light-curve modelers are studied, with a focus on the peak temperatures and the nucleosynthetic yields in each method. The various parameters involved in artificially initiating a shock wave and the effects of varying these parameters are discussed.