Conversion coefficients for superheavy elements

In this paper we report on internal conversion coefficients for Z = 111 to Z = 126 superheavy elements obtained from relativistic Dirac-Fock (DF) calculations. The effect of the atomic vacancy created during the conversion process has been taken into account using the so called "Frozen Orbital" approximation. The selection of this atomic model is supported by our recent comparison of experimental and theoretical conversion coefficients across a wide range of nuclei. The atomic masses, valence shell electron configurations, and theoretical atomic binding energies required for the calculations were adopted from a critical evaluation of the published data. The new conversion coefficient data tables presented here cover all atomic shells, transition energies from 1 keV up to 6000 keV, and multipole orders of 1 to 5. A similar approach was used in our previous calculations [1] for Z = 5 - 110.Comment: Accepted for publication in Atomic Data and Nuclear Data Table

Beech Leaves Briquettes’ and Standard Briquettes’ Combustion: Comparison of Flue Gas Composition

Biomass stoves are not only popular, widespread and important sources of heat but are also not negligible sources of pollutants. The present study had two objectives in this field of research. The first one was to determine the difference between standard wooden and beech leaves briquettes flue gas composition during similar, standard home combustion conditions. The second objective was to determine the possibility of decreasing the mass concentration of pollutants contained in the flue gas produced by standard and alternative fuel combustion, i.e. wooden briquettes and beech leaves briquettes, by an oxidation catalyst. Significantly higher mass concentration of nitrogen oxides (NOx), almost 2.5 times higher, in the flue gas was observed during the beech leaves combustion. Both fuels reached the edge of actual legislation limit (European Standard Commission regulation [EU] 2015/1185) in case of mass concentration of carbon monoxide (CO). This issue was solved by a palladium-based catalyst with average degree of conversion around 82%. The catalyst also influences flue gas composition from mass concentration of propane point of view with average degree of conversion around 15%. The mass fraction of sulphur, occurring in the beech leaves briquettes, did not cause any issue to the catalyst in terms of its degree of CO conversion. Due to the test results from the beech leaves briquettes, i.e. high mass fraction of ash and high mass concentration of NOx in the flue gas, it is appropriate to use this kind of fuel as secondary fuel during the co-combustion process.This work was supported by the Doctoral grant competition VŠB TU-Ostrava, reg. no. CZ.0 2.2.69/0.0./0.0/19_073/0016945 within the Operational Programme Research, Development and Education, under project DGS/TEAM/2020-035 "Determination of oxidation catalysts characteristics during the flue gas purification"

The first experimental evidence for the (M1+E2) mixed character of the 9.2 keV transition in Th-227

The 9.2 keV nuclear transition in Th-227 was studied in the beta(-)-decay of Ac-227 by means of the internal conversion electron spectroscopy to clarify the spin-parity assignment of the ground state and the two lowest excited states of Th-227. The transition multipolarity was proved to be of mixed character M1+ E2 and the spectroscopic admixture parameter delta(2)(E2/M1) = 0.695 +/- 0.248(vertical bar delta(E2/M1)vertical bar = 0.834 +/- 0.149) was determined. Nonzero value of delta(E2/M1) questioned the present theoretical interpretation of low-lying levels of Th-227. Calculations performed prefer the 1/2(+), 3/2(+), and 3/2(+) sequence instead of the adopted 1/2(+), 5/2(+) and 3/2(+) one for the 0.0, 9.2, and 24.3keV levels, respectively.Web of Science820art. no. 13659