Some Classifications of Biharmonic Lorentzian Hypersurfaces in Minkowski 5-Space

Mediterranean Journal of Mathematics - In this paper, we study Lorentzian hypersurfaces in Minkowski 5-space with non-diagonalizable shape operator whose characteristic polynomial is (t − k...     

The Effect of the Geometry of the Particle Distribution in Ostwald Ripening

Based on [1], we derive equations for the radii and the centers that we relate to the Lifshitz-Slyozov-Wagner theory. N.D.A. and G.K. were partially supported by a ENE 99/527 interdisciplinary grant in Materials, and by a grant from the University of Athens. N.D.A. would like to thank also the people at BYU for providing extraordinary hospitality and a stimulating environment during his visit in the Fall of 2000.N.D.A. and G.K. were partially supported by a ENE 99/527 interdisciplinary grant in Materials, and by a grant from the University of Athens. N.D.A. would like to thank also the people at BYU for providing extraordinary hospitality and a stimulating environment during his visit in the Fall of 2000.     

Space-Like Surfaces in the Minkowski Space with Pointwise 1-Type Gauss Maps

Ukrainian Mathematical Journal - We first classify space-like surfaces in the Minkowski space , de Sitter space , and hyperbolic space ?3 with harmonic Gauss maps. Then we characterize and...     

Expected Number of Real Roots for Random Linear Combinations of Orthogonal Polynomials Associated with Radial Weights

In this note, we obtain asymptotic expected number of real zeros for random polynomials of the form

$$f_{n}(z)=\sum\limits_{j=0}^{n}{a^{n}_{j}}{c^{n}_{j}}z^{j}$$

where \({a^{n}_{j}}\) are independent and identically distributed real random variables with bounded (2 + δ)th absolute moment and the deterministic numbers \({c^{n}_{j}}\) are normalizing constants for the monomials z ^j within a weighted L ²-space induced by a radial weight function satisfying suitable smoothness and growth conditions.

     

Synthesis and Characterization of Borax-Polyimide for Flame Retardant Applications

Polyamide-borax composites were prepared from solution of polyimide and the borax using N-methyl-2-pyrrolidone as a solvent. The Polyimide-borax composites films (PI-BX) characterized by FTIR, SEM and x-ray. The borax content significantly influences thermal behavior of the polymeric films, such as glass transition and decomposition temperatures of polyimide-borax composites. The glass transition temperatures of the composites were higher than that of the original polyimide. The flammability properties of them were demonstrated by cone calorimeter and indicate that the borax composites have significantly decreased in heat release rate, and mass loss rate. The PI-BX composites appears very good the flame retardant properties.     

A rational approximate solution for generalized pantograph‐delay differential equations

In this paper, a new rational approximation based on a rational interpolation and collocation method is proposed for the solutions of generalized pantograph equations. A comprehensive error analysis is provided. The first part of the error analysis gives an upper bound for the absolute error. The second part is based on residual error procedure that estimates the absolute error. Some numerical examples are given to illustrate the method. The theoretical results support the numerical results. Copyright © 2015 John Wiley & Sons, Ltd.     

Toeplitz Operators on Arveson and Dirichlet Spaces

We define Toeplitz operators on all Dirichlet spaces on the unit ball of and develop their basic properties. We characterize bounded, compact, and Schatten-class Toeplitz operators with positive symbols in terms of Carleson measures and Berezin transforms. Our results naturally extend those known for weighted Bergman spaces, a special case applies to the Arveson space, and we recover the classical Hardy-space Toeplitz operators in a limiting case; thus we unify the theory of Toeplitz operators on all these spaces. We apply our operators to a characterization of bounded, compact, and Schatten-class weighted composition operators on weighted Bergman spaces of the ball. We lastly investigate some connections between Toeplitz and shift operators. The research of the second author is partially supported by a Fulbright grant.