The Jacobian-Free Newton-Krylov (JFNK) method has been widely used in solving nonlinear equations arising in many applications. In this paper, the JFNK solver is examined as an alternative to the traditional power iteration method for calculation of the fundamental eigenmode in reactor analysis based on Even-parity neutron transport theory. Since the Jacobian is not formed the only extra storage required is associated with the workspace of the Krylov solver used at every Newton step. A new nonlinear function is developed for the Even-parity neutron transport equation utilized to solve the eigenvalue problem using the JFNK. This Newton-based method is compared with the standard iterative power method for a number of multi-groups, one and two dimensional neutron transport benchmarks. The results show that the proposed algorithm generally ends with fewer iterations and shorter run times than those of the traditional power method.

The objective of this paper is to introduce a new direct method for neutronic calculations. This method, called Direct Discrete Method (DDM), is simpler than the neutron transport Equation and more compatible with the physical meanings of the problem. The method, based on the physics of the problem, initially runs through meshing of the desired geometry. Next, the balance equation for each mesh interval is written. Considering the connection between the mesh intervals, the final discrete equation series are directly obtained without the need to first pass through the set-up of the neutron transport differential equation. In this paper, a single and multi-group neutron transport discrete equation has been produced for a cylindrical shape fuel element with and without the associated clad and the coolant regions, each with two different external boundary conditions. The validity of the results from this new method are tested against the results obtained by the MCNP-4B and the ANISN codes.  

The sd-version of the interacting boson model (IBM) is used to establish the shape phase transitional structure. A simplified Hamiltonian is used which is intermediate between the three dynamical symmetries of U (6), namely the spherical U (5), the prolate and oblate deformed SU (3) and the g-unstable O (6) limits. The potential energy surfaces (PESs) to the IBM Hamiltonian have been obtained using the intrinsic state formalism which introduces the shape variables b and g. The Gadolinium (Gd) and Ruthenium (Ru) isotopic chains have been taken as examples in illustrating the U (5)-SU (3) and U (5) - O (6) shape phase transitions, respectively. We used the standard c2 test to get the IBM Hamiltonian parameters. The fit is performed by minimizing the c2 function for some selected experimental low-lying energy levels, the two neutron separation energies and B (E2) transition rates.

Background: Pregnancy is associated with structural and functional changes in the cardiovascular system as well as obesity, high blood triglyceride concentration, and increased risk of metabolic syndrome.Objective: The aim of this study was to compare parity between women with established coronary heart disease and normal women in general population.Materials and Methods: Totally, 105 women referred for coronary artery bypass grafting surgery during a period of more than one year were enrolled. Total fertility rate (TFR) was evaluated in this group of patients and we also compared TFR of these women with that of normal women.Results: Based on the results, 884 pregnancies were occurred in total of 105 patients (mean parity=8.34). There was a significant difference between the TFR of the CABG patients and the TFR of the normal women in 1966 (p value=0.038), the TFR of the normal women in the past 40 years (p value<0.001), the TFR of the normal women in province of Sistan and Baluchistan (p value<0.001).Conclusion: Our findings suggest that the number of pregnancy is an independent risk factor associated with coronary artery disease.

We show that for each positive integer n, there exist a group G and a subgroup H such that the ordinary depth d(H,G) is 2n. This solves the open problem posed by Lars Kadison whether Even ordinary depth larger than 6 can occur.

Fast neutrons that are produced via compact neutron generators have been used for thermal and fast neutron radiographies. In order to investigate objects with different sizes and produce radiographs of variable qualities, the proposed facility has been considered with a wide range of values for the parameters characterizing the thermal and fast neutron radiographies. The proposed system is designed according to article 4 of the Restriction of Hazardous Substances Directive 2002/95/EC, hence, excluded the use of cadmium and lead, and has been simulated using the MCNP4B code. The Monte Carlo calculations were carried out using three different neutron sources: deuterium-deuterium, deuterium-tritium, and tritium-tritium neutron generators.