scholarly journals Description of the Fission Process: Nuclear Models for Fission Dynamics

2020 ◽  
Vol 242 ◽  
pp. 03005
Author(s):  
M. Verriere ◽  
M.R. Mumpower ◽  
T. Kawano ◽  
N. Schunck

Nuclear fission is the splitting of a heavy nucleus into two or more fragments, a process that releases a substantial amount of energy. It is ubiquitous in modern applications, critical for national security, energy generation and reactor safeguards. Fission also plays an important role in understanding the astrophysical formation of elements in the universe. Eighty years after the discovery of the fission process, its theoretical understanding from first principles remains a great challenge. In this paper, we present promising new approaches to make more accurate predictions of fission observables.

2020 ◽  
Vol 1 (1) ◽  
pp. 65-83
Author(s):  
Božidar Forca ◽  
Dragoljub Sekulović ◽  
Igor Vukonjanski

Security is one of the most common terms in the modern world. This statement is supported by the fact that the term security is used in a wide range of areas. The subject of this paper is national security and the challenges, risks and threats to that security in contemporary international relations. The purpose of the work is twofold. First, to show the diversity of theoretical understanding of the term challenge, risk and threat by various authors. On the other hand, the overriding goal is to analyze the relationship to the challenges, risks and threats in different countries. When it comes to national security, challenges, risks and threats, most often, are identified in a document called the national security strategy. This document, as one of the highest in the hierarchy of political acts of every state, when it comes to security, is passed by almost all modern states of the world. The analysis of numerous national security strategies has revealed that it is possible to identify: 1) the challenges, risks and threats that appear in all strategies, 2) the challenges, risks and threats of security that appear in most strategies, and 3) the challenges, risks and threats of security which are country specific.


1999 ◽  
Vol 14 (06) ◽  
pp. 815-843 ◽  
Author(s):  
M. J. DUFF

There has recently been a revival of interest in anti-de-Sitter space (AdS), brought about by the conjectured duality between physics in the bulk of AdS and a conformal field theory on the boundary. Since the whole subject of branes, singletons and superconformal field theories on the AdS boundary was an active area of research about ten years ago, we begin with a historical review, including the idea of the "membrane at the end of the universe." We then compare the old and new approaches and discuss some new results on AdS 5 × S5 and AdS 3 × S3.


2022 ◽  
Author(s):  
Emily Riehl ◽  
Dominic Verity

The language of ∞-categories provides an insightful new way of expressing many results in higher-dimensional mathematics but can be challenging for the uninitiated. To explain what exactly an ∞-category is requires various technical models, raising the question of how they might be compared. To overcome this, a model-independent approach is desired, so that theorems proven with any model would apply to them all. This text develops the theory of ∞-categories from first principles in a model-independent fashion using the axiomatic framework of an ∞-cosmos, the universe in which ∞-categories live as objects. An ∞-cosmos is a fertile setting for the formal category theory of ∞-categories, and in this way the foundational proofs in ∞-category theory closely resemble the classical foundations of ordinary category theory. Equipped with exercises and appendices with background material, this first introduction is meant for students and researchers who have a strong foundation in classical 1-category theory.


2018 ◽  
Vol 169 ◽  
pp. 00024 ◽  
Author(s):  
F. Tovesson ◽  
D. Duke ◽  
V. Geppert-Kleinrath ◽  
B. Manning ◽  
D. Mayorov ◽  
...  

Different aspects of the nuclear fission process have been studied at Los Alamos Neutron Science Center (LANSCE) using various instruments and experimental techniques. Properties of the fragments emitted in fission have been investigated using Frisch-grid ionization chambers, a Time Projection Chamber (TPC), and the SPIDER instrument which employs the 2v-2E method. These instruments and experimental techniques have been used to determine fission product mass yields, the energy dependent total kinetic energy (TKE) release, and anisotropy in neutron-induced fission of U-235, U-238 and Pu-239.


2001 ◽  
Vol 666 ◽  
Author(s):  
Yanfa Yan ◽  
S.B. Zhang ◽  
S.J. Pennycook ◽  
S.T. Pantelides

ABSTRACTWe present results of a comprehensive set of first-principles total-energy calculations of native and impurity-defect complexes in ZnO and use these results to elucidate the problems that occur in efforts to achieve p-type doping. The analysis naturally leads to new approaches that are likely to overcome the difficulties. The results provide detailed explanations of recent puzzling observations made in attempts to produce p-type ZnO.


2004 ◽  
Vol 218 ◽  
pp. 357-364 ◽  
Author(s):  
Anatoly Spitkovsky

I review the theoretical understanding of the global structure of pulsar magnetospheres concentrating on recent progress in force-free electrodynamics and first-principles simulations of magnetospheres.


2009 ◽  
Vol 18 (04) ◽  
pp. 767-772 ◽  
Author(s):  
J. TAIEB ◽  
G. BELIER ◽  
A. CHATILLON ◽  
T. GRANIER ◽  
A. KELIC ◽  
...  

A novel experimental program aiming to study the properties of fragments and neutrons emitted in the fission process has been initiated. The experiment will be held at the ELISe electron-ion collider to be constructed at GSI, Darmstadt in the framework of the FAIR extension of the facility. The experiment will take advantage of the inverse kinematics allowing, in particular, a total mass and charge resolution for all fission fragments.


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