The four existing stable factorization methods for symmetric indefinite pivoting (row or column exchanges) maintains a band structure in the reduced matrix and the factors, but destroys symmetry completely once an off-diagonal pivot is used. Two-by-two block pivoting maintains symmetry at all times, but quickly destroys the band structure. Gaussian reduction to tridiagonal also maintains symmet...

This paper reviews the recent progress in the analysis and applications of the symmetry-related electromagnetic properties of transmission lines loaded with symmetric configurations of resonant elements. It will be shown that the transmission characteristics of these reactively loaded lines can be controlled by the relative orientation between the line and the resonant elements. Two main types ...

We study the evolution of a viscous fluid drop rotating about a fixed axis at constant angular velocity Ω or constant angular momentum L surrounded by another viscous fluid. The problem is considered in the limit of large Ekman number and small Reynolds number. The analysis is carried out by combining asymptotic analysis and full numerical simulation by means of the boundary element method. We ...

This paper details the development of the fixed grid FEA (FGFEA) method to the solution of eigenvalue (natural frequency and buckling) problems, using a 4 node 20 degree of freedom shell element. The formulation of the FG element stiffness, buckling and natural frequency equations is presented. The first natural frequency and buckling load are determined for the simply supported plate with a ce...

Within the quasiparticle random-phase approximation (QRPA) we achieve partial restoration of the isospin symmetry and hence fulfillment of the requirement that the 2νββ Fermi matrix element M F vanishes, as it should, unlike in the previous version of the method. This is accomplished by separating the renormalization parameter gpp of the particle-particle proton-neutron interaction into isovect...

Although the weak nonleptonic amplitudes of the Standard Model are notoriously difficult to calculate, we have produced a modified weak matrix element which can be analyzed using reliable methods. This hypothetical nonleptonic matrix element is expressible in terms of the isovector vector and axialvector spectral functions ρV(s) and ρA(s), which can be determined in terms of data from tau lepto...

Magnetic skyrmions are topological magnetic structures, which exhibit quasi-particle properties and can show enhanced stability against perturbation from thermal noise. Recently, Brownian diffusion of these quasi-particles has been found in continuous films applications unconventional computing have received significant attention, however require structured elements. Thus, as the next necessary...

FINGER iS a Lisp-based system to derive formulas needed in finite element analysis, and to generate FORTRAN code from these formulas. The generated programs can be used with existing, FORTRAN-based finite element analysis packages. This approach aims to replace tedious hand computations that are time consuming and error prone. The design and implementation of FINGER are presented. Techniques fo...

An antenna array element failure problem is one of the practical and challenging issues in the field of adaptive beamforming. The complete radiation pattern of the array is distorted when any one of the elements fails. Sidelobes level increases, nulls are shifted and null depth is also decreased tremendously. In order to mitigate the problem, we have given a new and easy approach coined as conj...