On the role of the second well of the deformation potential energy in nuclear fission in the lead region

1989 ◽  
Vol 333 (4) ◽  
pp. 389-392
Author(s):  
E. M. Rastopchin ◽  
G. N. Smirenkin ◽  
V. V. Pashkevich
1967 ◽  
Vol 57 (3) ◽  
pp. 341-371 ◽  
Author(s):  
R. Burridge ◽  
L. Knopoff

abstract A laboratory and a numerical model have been constructed to explore the role of friction along a fault as a factor in the earthquake mechanism. The laboratory model demonstrates that small shocks are necessary to the loading of potential energy into the focal structure; a large part, but not all, of the stored potential energy is later released in a major shock, at the end of a period of loading energy into the system. By the introduction of viscosity into the numerical model, aftershocks take place following a major shock. Both models have features which describe the statistics of shocks in the main sequence, the statistics of aftershocks and the energy-magnitude scale, among others.


2007 ◽  
Vol 118 (3) ◽  
pp. 649-663 ◽  
Author(s):  
Rachel Crespo-Otero ◽  
Yoana Pérez-Badell ◽  
Juan Alexander Padrón-García ◽  
Luis Alberto Montero-Cabrera

2018 ◽  
Vol 178 ◽  
pp. 05007 ◽  
Author(s):  
Ashok Kumar Jain ◽  
Swati Garg

It is generally believed that isospin would diminish in its importance as we go towards heavy mass region due to isospin mixing caused by the growing Coulomb forces. However, it was realized quite early that isospin could become an important and useful quantum number for all nuclei including heavy nuclei due to neutron richness of the systems [1]. Lane and Soper [2] also showed in a theoretical calculation that isospin indeed remains quite good in heavy mass neutron rich systems. In this paper, we present isospin based calculations [3, 4] for the fission fragment distributions obtained from heavy-ion fusion fission reactions. We discuss in detail the procedure adopted to assign the isospin values and the role of neutron multiplicity data in obtaining the total fission fragment distributions. We show that the observed fragment distributions can be reproduced rather reasonably well by the calculations based on the idea of conservation of isospin. This is a direct experimental evidence of the validity of isospin in heavy nuclei, which arises largely due to the neutron-rich nature of heavy nuclei and their fragments. This result may eventually become useful for the theories of nuclear fission and also in other practical applications.


Author(s):  
B S Knight ◽  
J H Davies ◽  
F A Capitanio

Summary The relatively short duration of the early stages of subduction results in a poor geological record, limiting our understanding of this critical stage. Here, we utilize a 2D numerical model of incipient subduction, that is the stage after a plate margin has formed with a slab tip that extends to a shallow depth and address the conditions under which subduction continues or fails. We assess energy budgets during the evolution from incipient subduction to either a failed or successful state, showing how the growth of potential energy, and slab pull, is resisted by the viscous dissipation within the lithosphere and the mantle. The role of rheology is also investigated, as deformation mechanisms operating in the crust and mantle facilitate subduction. In all models, the onset of subduction is characterized by high lithospheric viscous dissipation and low convergence velocities, whilst successful subduction sees the mantle become the main area of viscous dissipation. In contrast, failed subduction is defined by the lithospheric viscous dissipation exceeding the lithospheric potential energy release rate and velocities tend towards zero. We show that development of a subduction zone depends on the convergence rate, required to overcome thermal diffusion and to localise deformation along the margin. The results propose a minimum convergence rate of ∼ 0.5 cm yr−1 is required to reach a successful state, with 100 km of convergence over 20 Myr, emphasizing the critical role of the incipient stage.


2016 ◽  
Vol 18 (4) ◽  
pp. 3011-3022 ◽  
Author(s):  
Yu-Ting Chen ◽  
Kerwin Hui ◽  
Jeng-Da Chai

We investigate the potential energy curves of rare-gas dimers with various ranges and strengths of interparticle interactions (nuclear–electron, electron–electron, and nuclear–nuclear interactions).


1995 ◽  
Vol 10 ◽  
pp. 597-598
Author(s):  
R. Wehrse

An accretion disk is formed when matter with angular momentum is flowing on a gravitating object (as e.g. a white dwarf, a neutron star, a young stellar object, or a black bole). It radiates because the transport of angular momentum (required for the matter to reach the central object) necessarily implies the conversion of potential energy into a form of energy that corresponds to higher entropy. Many aspects of the physics (as e.g. the mechanism for the heat generation) are not yet well understood but they are presently one of the centers of astronomical interest (see e.g. the books by Frank, King, and Raine, 1992, or by Wheeler, 1993).


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