Anjul M. Davis

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Introduction: Twenty-five years after the discovery of meteoritic nanodiamonds, their origins are still unknown. Isotopic anomalies in Xe, Ba, Pd, and Te found in bulk samples of nanodiamonds can be only explained by stellar nucleosynthesis and hence indicate a presolar origin [1–4]. In contrast, C and N isotopic ratios of bulk nanodiamonds are close to(More)
Introduction: Recent improvements to the CHARISMA instrument at Argonne National Laboratory have enabled the first four-isotope measurements of Cr in presolar SiC grains. Resonance ionization mass spectrometry (RIMS), which uses tuned lasers to excite and ionize atoms of a single element of interest from a cloud of desorbed neutral atoms, permits the(More)
We are now constructing the ion nanoprobe, a new instrument designed for isotopic and chemical analysis at the few-nm scale. The new instrument will combine a recently developed high resolution liquid metal ion gun (LMIG), tunable solid state lasers for laser resonant ionization, a molecular fluorine excimer laser for UV ionization, and high transmission,(More)
In this paper, stress and strain equations are developed for the left ventricle mainly to nd the innuence of the ventricle's shape on wall stresses. Here, the ventricle is assumed to be a thick-walled truncated conical shell and large elastic deformation theory is applied. Our model is compared to corresponding results approximating the left ventricle as a(More)
Introduction: Presolar SiC grains, isolated from acid residues of primitive meteorites, are ejecta of stars that contributed to the protosolar nebula. Due in part to SiC's refractory, chemically inert nature, these grains have survived solar system formation to provide an isotopic record of the nuclear processing in their parent stars. Among these grains(More)
Introduction: The 182 Hf– 182 W decay system (t 1/2 =9 My) provides a useful chronometer of early solar system processes, notably metal-silicate differentiation [1-8]. Hf-W systematics of refractory inclusions indicate that these objects formed with an initial 182 Hf/ 180 Hf ratio of ~1×10-4 and an initial ε 182 W of –3.47 ± 0.20 [6]. Some iron meteorites(More)
Introduction: The IVB iron meteorites have been described as highly homogeneous on a fine scale [1]. This group is also enriched in many siderophile trace elements [2,3]. For these reasons, the Hoba IVB iron has been used as a concentration standard in numerous trace element studies of metallic samples using laser-ablation ICPMS [e.g., 4,5]. In conjunction(More)
Introduction: Eighty five percent of 93 Nb, the only stable isotope of niobium, is produced by s-process nu-cleosynthesis in low mass asymptotic giant branch (AGB) stars as radioactive 93 Zr (t 1/2 = 1.5×10 6 y) [1]. Due to its short half-life compared to the lifetime of low mass stars (~10 9 y), 93 Zr in stars must be synthesized locally and cannot be(More)