A consistent description of the nuclear α-decay process
The essential features of a new theory of α decay and the need for such a theory are reviewed. An approximate relationship between half life and α-particle energy is deduced and checked for the decay of even polonium isotopes. Detailed calculations of one-body widths and spectroscopic factors for the polonium decays are presented and the implications of the results are discussed. It is also shown that the result for the α decay of 212Po is consistent with the reverse α-transfer reaction.
ALPHA-DECAY OF HEAVY AND SUPERHEAVY NUCLEI
Methods of calculating alpha-decay lifetimes are reviewed with particular emphasis on the uncertainties which arise in calculations of barrier penetration. A new approach is presented which removes most of the earlier ambiguities and uncertainties. The role of antisymmetrization between the α-particle and the residual nucleus is examined and methods of taking this into account are discussed. Results are given for nuclei with mass number A = 212, A = 294−302, and A = 342.
Quantitative and qualitative relationship between swirl burner operatingconditions and pulverized coal flame length
Abstract Currently, there are used in power plants two types of burners to combustion the pulverized coal: jet burners and swirl burners. Most of the published works in the field of analysis of burners operating conditions are related to jet burners and are limited to initial region of the flame at the outlet of the burner. For jet burners an offset between the burner outlet and the flame beginning point could be analyzed. In the case of swirl burners with the pre-mixing diffuser chamber an offset between flame ignition point and burner outlet is usually not visible. Because already in the pre-mixing diffuser chamber of swirl burner occurs the ignition of coal-dust together with oxidant-gas cloud and thereby the formation of the flame. Therefore, the analysis of operating conditions for this types of burners requires a different approach. There is a lack of researches, in which will be analyzed changes of the flame length, that are caused by changes of design and operating parameters of swirl burner with the pre-mixing diffuser chamber. Therefore the aim of this study was to implement and verify the methodology for estimating the flame length, which will allow monitoring changes of operating conditions, that are caused by changes of design and operating parameters of swirl burner with the pre-mixing diffuser chamber. To carry out the analysis of the image of the coal flame, the two algorithms have been presented. This two algorithms, being based on the video images of the coal flame allows to specify and detect the end point of the flame and on that basis the length of the flame, as well as the fluctuation changes of flame length can be later determined. Both, the change thermal loads of coal burner, streams of secondary air, as well as the constructional change of the angle of swirler assemblies, resulted in distinct changes in the length of the pulverized coal flame.