An analytical method to find the flow generated by the basic singularities of Stokes flow in a wedge of arbitrary angle is presented. Specifically, we solve a biharmonic equation for the stream function of the flow generated by a point stresslet singularity and satisfying no-slip boundary conditions on the two walls of the wedge. The method, which is readily adapted to any other singularity typ...

We define the notion of a finite-time singularity of a vector field and then discuss a technique suitable for the asymptotic analysis of vector fields and their integral curves in the neighborhood of such a singularity. Having in mind the application of this method to cosmology, we also provide an analysis of the time singularities of an isotropic universe filled with a perfect fluid in general...

Hawking radiation is computed in different coordinate systems using the method of complex paths. In this procedure the event horizon of the 2D Schwarzschild stringy black hole is treated as a singularity for the semiclassical action functional. After the regularization of the event horizon’s singularity the emission/absorption probabilities and the Hawking temperature in the different coordinat...

This paper combine two conventional feature extraction methods (NWFE&NPE) in a novel framework and present a new semisupervised feature extraction method called Adjusted Semi supervised Discriminant Analysis (ASEDA). The advantage of this method is dominating the Hughes phenomena, automatic selection of unlabelled pixels, extraction of more than L-1(L: number of classes) features and avoidance ...

The method of Gaussian wave packet (GWP) propagation introduced by Heller is a popular tool for doing time dependent quantum mechanical calculations in particular in molecular and in nuclear physics. We show that this method is also applicable to atomic systems. We concentrate on the H-atom in a strong magnetic field, where a well-known regularization is used to remove the singularity. The Coul...

The finite element method (FEM) is applied to bound leading eigenvalues of the Laplace operator over polygonal domains. Compared with classical numerical methods, most of which can only give concrete eigenvalue bounds over special domains of symmetry, our proposed algorithm can provide concrete eigenvalue bounds for domains of arbitrary shape, even when the eigenfunction has a singularity. The ...

A new kind of numerical method based on rational spectral collocation with the sinh transformation is presented for solving parameterized singularly perturbed two-point boundary value problems with one boundary layer. By means of the sinh transformation, the original Chebyshev points are mapped onto the transformed ones clustered near the singular points of the problem. The results from asympto...

A concurrent multigrid method is devised for the direct estimation of stress intensity factors (SIF) and higher order coefficients of the elastic crack tip asymptotic field. The proposed method bridges three characteristic length scales that can be present in fracture mechanics: the structure, the crack and the singularity at the crack tip. For each of them, a relevant model is proposed. First,...

A singularity image method is applied to the electrical impedance tomography of gas–liquid flows in a two-dimensional circular domain. Algorithms that use analytic complex functions, dipoles and the Milne-Thomson circle theorem are described. Numerical experiments are provided to demonstrate the robustness of this technique. Numerical results show excellent reconstruction properties. (Some figu...

Characterization of the stability boundary of differential-algebraic (DAE) systems is more complicated than for systems described by ordinary differential equations (ODEs). In addition to unstable equilibria and periodic orbits, algebraic singularity plays an important role in defining the stability boundary. This paper presents a Lyapunov-based method for direct assessment of transient singula...