Superconducting Properties of Carbonaceous Chemical Doped MgB2

The discovery of superconductivity in magnesium diboride (MgB2: 39 K, in January 2001) (Nagamatsu et al., 2001) has generated enormous interest and excitement in the superconductivity community and the world in general, but especially among researchers into superconductivity in non-oxide and boron related compounds

Assessing the implementation of Sustainable Development Goals through switching cost

An increasing number of corporations are adapting their strategies to include projects aimed at achieving United Nations’ Sustainable Development Goals. Nonetheless, the implementation of these projects revives a fifty-year old question about the impact of sustainable activity on corporate financial performance and sustainability outcomes. This paper proposes the analysis of the Switching Costs of sustainable projects as a way to identify areas of improvement for corporate strategies, thus responding to the urgent need for models and assessment tools able to achieve financial and sustainability objectives as claimed by both practice and academia. A conceptual framework relating the Switching Costs of sustainable projects to sustainability and corporate financial performance has been developed and applied in this research to a case-study company, Walmart Mexico and Central America. This paper addresses the challenge of recognising, collecting and gauging the effect of the changes, particularly those of an intangible nature, generated by the sustainable projects

Coronal lines and the importance of deep core-valence correlation in Ag-like ions

We report on large-scale and critically evaluated {\em ab initio} MCDHF calculations of the wavelength of the "coronal", M1 transition $4f\ ^2\mathrm{F}_{5/2}^o-^2\mathrm{F}_{7/2}^o$in Ag-like ions. The transition between these two fine structure levels, which makes up the ground term for$Z \ge 62$in the isoelectronic sequence, has recently been observed in Yb$^{23+}$and W$^{27+}$, where the latter could be of great importance for fusion plasma diagnostics. We present recommended values for all members of the sequence between$Z = 50$and$94$, which are supported by excellent agreement with values from recent experiments. The importance of including core-valence correlation with the$n=3$ shell in the theoretical model is emphasized. The results show close to spectroscopic accuracy for these forbidden lines.Comment: 10 pages, 5 figures, 3 table

The effect of an external magnetic field on the determination of E1M1 two-photon decay rates in Be-like ions

In this work we report on ab initio theoretical results for the magnetic field induced 2s2p ^3P_0 - 2s^2 ^1S_0 E1 transition for ions in the beryllium isoelectronic sequence between Z=5 and 92. It has been proposed that the rate of the E1M1 two-photon transition 2s2p ^3P_0 - 2s^2 ^1S_0 can be extracted from the lifetime of the ^3P_0 state in Be-like ions with zero nuclear spin by employing resonant recombination in a storage-ring. This experimental approach involves a perturbing external magnetic field. The effect of this field needs to be evaluated in order to properly extract the two-photon rate from the measured decay curves. The magnetic field induced transition rates are carefully evaluated and it is shown that, with a typical storage-ring field strength, it is dominant or of the same order as the E1M1 rate for low- and mid-Z ions. Results for several field strengths and ions are presented and we also give a simple Z-dependent formula for the rate. We estimate the uncertainties of our model to be within 5% for low- and mid-Z ions, and slightly larger for more highly charged ions. Furthermore we evaluate the importance of including both perturber states, ^3P_1 and ^1P_1, and it is shown that excluding the influence of the ^1P_1 perturber overestimates the rate by up to 26% for the mid-Z ions.Comment: 21 pages, 5 figure