Isospin Dependence in the Odd-Even Staggering of Nuclear Binding Energies

The FRS-ESR facility at GSI provides unique conditions for precision measurements of large areas on the nuclear mass surface in a single experiment. Values for masses of 604 neutron-deficient nuclides (30<=Z<=92) were obtained with a typical uncertainty of 30 microunits. The masses of 114 nuclides were determined for the first time. The odd-even staggering (OES) of nuclear masses was systematically investigated for isotopic chains between the proton shell closures at Z=50 and Z=82. The results were compared with predictions of modern nuclear models. The comparison revealed that the measured trend of OES is not reproduced by the theories fitted to masses only. The spectral pairing gaps extracted from models adjusted to both masses, and density related observables of nuclei agree better with the experimental data.Comment: Physics Review Letters 95 (2005) 042501 http://link.aps.org/abstract/PRL/v95/e04250

Present and Future Experiments with Stored Exotic Nuclei at Relativistic Energies

Recent progress is presented from experiments on masses and lifetimes of bare and few-electron exotic nuclei at GSI.Comment: Proceedings of International Conference on "Frontiers in Nuclear Structure, Astrophysics and Reactions", Kos, Greece, September 12-17, 200

α-Mg primary phase formation and dendritic morphology transition in solidification of a Mg-Nd-Gd-Zn-Zr casting alloy

Microstructure evolution in the commercial Mg-Nd-Gd-Zn-Zr alloy Elektron 21, solidified under nearly isothermal conditions, has been studied via in-situ X-ray radiography. For cooling rates View the MathML sourceT˙≤0.075 K/s, primary equiaxed α-Mg dendrites undergo a morphological transition after nucleation and an initial stage of growth. The growth regime is observed to change abruptly from a 3D to a more pronounced anisotropic sheet-like growth occurring predominantly along View the MathML source112¯0 direction, with a 4–5 times increase in the growth velocity. The experimental results together with thermodynamic calculations and density functional theory simulations give support to relate the morphology transition to the formation of ordered rare earth-zinc dimers in the {0001}{0001} basal plane and View the MathML source{101¯1} pyramidal plane of α-Mg lattice. At the temperature where the morphological transition occurs, it is found that both the solute concentration and zinc diffusivity in α-Mg are high enough for dimer formation to occur within a diffusive layer extending a few micrometres from the solid-liquid interface into α-Mg, and thereby open for increased solute-partitioning at the growth front

Non-steady 3D dendrite tip growth under diffusive and weakly convective conditions

Three dimensional α-Al dendrite tip growth under varying solute gradients in an Al-Cu-Si alloy melt has been studied using real time synchrotron X-ray imaging and mathematical modelling. X-radiographic image sequences with high temporal and spatial resolution were processed and analysed to retrieve three-dimensional spatial details of the evolving dendrite and the solute concentration field, providing vastly improved estimates for the latter, in particular for the melt regions adjacent to the dendrite tips. Computational results obtained from an extended Horvay-Cahn dendrite tip model, capable of taking into account the effects of sample confinement, showed good agreement with the experimental data, and can be taken to verify the robustness of the 3D data extraction protocol.European Commission - Seventh Framework Programme (FP7)Engineering and Physical Sciences Research Council (EPSRC) UKNorwegian Research Council, SYNKNOYT programm

The Oslo Health Study: Is bone mineral density higher in affluent areas?

<p>Abstract</p> <p>Background</p> <p>Based on previously reported differences in fracture incidence in the socioeconomic less affluent Oslo East compared to the more privileged West, our aim was to study bone mineral density (BMD) in the same socioeconomic areas in Oslo. We also wanted to study whether possible associations were explained by socio-demographic factors, level of education or lifestyle factors.</p> <p>Methods</p> <p>Distal forearm BMD was measured in random samples of the participants in The Oslo Health Study by single energy x-ray absorptiometry (SXA). 578 men and 702 women born in Norway in the age-groups 40/45, 60 and 75 years were included in the analyses. Socioeconomic regions, based on a social index dividing Oslo in two regions – East and West, were used.</p> <p>Results</p> <p>Age-adjusted mean BMD in women living in the less affluent Eastern region was 0.405 g/cm²and significantly lower than in West where BMD was 0.419 g/cm². Similarly, the odds ratio of low BMD (Z-score ≤ -1) was 1.87 (95% CI: 1.22–2.87) in women in Oslo East compared to West. The same tendency, although not statistically significant, was also present in men. Multivariate analysis adjusted for education, marital status, body mass index, physical inactivity, use of alcohol and smoking, and in women also use of post-menopausal hormone therapy and early onset of menopause, did hardly change the association. Additional adjustments for employment status, disability pension and physical activity at work for those below the age of retirement, gave similar results.</p> <p>Conclusion</p> <p>We found differences in BMD in women between different socioeconomic regions in Oslo that correspond to previously found differences in fracture rates. The association in men was not statistically significant. The differences were not explained by socio-demographic factors, level of education or lifestyle factors.</p

Thermodynamics of the Atomic Distribution in Pt3Pd2, Pt2Pd3 and their Corresponding (111) Surfaces

In this study, we have developed solid-state models of platinum and palladium bimetallic catalysts, Pt3Pd2 and Pt2Pd3, which are rapidly thermally annealed at 800 °C. These models were constructed by determining all the unique atomic configurations in a 2x2x1 supercell, using the program Site-Occupation Disorder (SOD), and optimized with the General Utility Lattice Program (GULP) using Sutton-Chen interatomic potentials. Each catalyst had 101 unique bulk models that were developed into surface models, which were constructed using the two-region surface technique before the surface energies were determined. The planes and compositions with lowest surface energies were chosen as the representative models for the surface structure of the bimetallic catalysts. These representative models will now be used in a computational study of the HyS process for the production of hydrogen