122026076
Role of nuclear dissipation and entrance channel mass asymmetry in pre-scission neutron multiplicity enhancement in fusion-fission reactions
Pre-scission neutron multiplicities are measured for ${}^{12}\mathrm{C} + {}^{204}\mathrm{Pb}$ and ${}^{19}\mathrm{F} + {}^{197}\mathrm{Au}$ reactions at laboratory energies of 75\char21{}95 MeV for the $^{12}\mathrm{C}$ beam and 98\char21{}118 MeV for the $^{19}\mathrm{F}$ beam. The chosen projectile-target combinations in the present study lie on either side of the Businaro-Gallone mass asymmetry (${\ensuremath{\alpha}}_{\mathrm{BG}}$) and populate the $^{216}\mathrm{Ra}$ compound nucleus. The dissipation strength is deduced after comparing the experimentally measured neutron yield with the statistical model predictions which contains the nuclear viscosity as a free parameter. Present results demonstrate the combined effects of entrance channel mass asymmetry and the dissipative property of nuclear matter on the pre-scission neutron multiplicity in fusion-fission reactions.
120945477
On improvement of charge resolution of cosmic ray particles using a cellulose nitrate plastic detector
Abstract By employing improved procedures of measurement and analysis we have been able to obtain good charge resolution for stopping cosmic ray nuclei with Z ⩽30 in a cellulose nitrate detector. In a particular, it has been found that ( V t V b ) provides a much more reliable measure of ionisation loss than cone length. A charge resolution of 0.2 charge units for nuclei with Z ≲20 and of 0.3 charge units for nuclei with Z > 20 has been achieved in the present experiment.
122194176
Search for entrance channel effects in heavy ion induced fusion reactions via neutron evaporation
120052850
Search for entrance channel effects in heavy ion induced fusion reactions through the compound system79Rb
120377524
Measurement of neutron multiplicity from fission of {sup 228}U and nuclear dissipation
Pre- and post-scission neutron multiplicities are measured at different excitation energies of the compound nucleus {sup 228}U populated using the {sup 19}F+{sup 209}Bi reaction. The measured yield of pre-scission and total neutrons are compared with the statistical model calculation for the decay of a compound nucleus. The statistical model calculations are performed using the Bohr-Wheeler transition state fission width as well as the dissipative dynamical fission width due to Kramers. Comparison between the measured and the calculated values shows that, while the Bohr-Wheeler fission width grossly underestimates the pre-scission neutron yield, a large amount of dissipation is required in the Kramers width to fit the experimental pre-scission multiplicities. Various factors contributing to the large excitation energy dependence of the fitted values of the dissipation coefficient are discussed.
121342913
Higher-dimensional cosmological model with variable gravitational constant and bulk viscosity in Lyra geometry
We have studied five-dimensional homogeneous cosmological models with variableG and bulk viscosity in Lyra geometry. Exact solutions for the field equations have been obtained and physical properties of the models are discussed. It has been observed that the results of new models are well within the observational limit.
122105066
Anisotropic bulk viscous cosmological models with particle creation
This paper is devoted to the study of role of particle creation and bulk viscosity on evolution of homogeneous and anisotropic model of the universe represented by Bianchi type I space time metric. Particle creation and bulk viscosity have been considered as separated irreversible processes. In order to discuss physical and geometrical behaviour of the model, a new set of exact solutions of Einstein’s field equation have been obtained in non-causal, truncated and full causal theories. Dynamical behaviours of models have also been discussed.
122378029
Bianchi type I bulk viscous cosmological models with particle creation in Brans-Dicke theory
This paper is devoted to the study of the role of particle creation and bulk viscosity in the evolution of the homogeneous and anisotropic model of the universe represented by Bianchi type I space-time metric in Brans-Dicke theory. Particle creation and bulk viscosity have been considered as separated irreversible processes. In order to discuss the physical and geometrical behaviour of the model, a new set of exact solutions of field equations have been obtained in non-causal, truncated and full causal theories. The dynamical behaviours of models have also been discussed.
121973847
Liouville space-time in general projective relativity
Vacuum field equations of general projective relativity have been solved for Liouville space-time. Finally harmonic coordinate condition and singular behaviour of Kretschmann scalar for the solution is discussed.
122085578
Static models of cosmic strings in general relativity
Exact solutions to Einstein’s equations for a cloud of massive strings with a general static metric representing spherical plane and hyperbolic symmetries are derived. Some properties of massive strings for different cases are also discussed.