2004 ◽  
Vol 45 (9) ◽  
pp. 3533-3545 ◽  
Author(s):  
A. Amaya-Tapia ◽  
G. Gasaneo ◽  
S. Ovchinnikov ◽  
J. H. Macek ◽  
S. Y. Larsen

Author(s):  
M. Seredyńska ◽  
A. Hanyga

Viscoelastic materials have non-negative relaxation spectra. This property implies that viscoelastic response functions satisfy certain necessary and sufficient conditions. These conditions can be expressed in terms of each viscoelastic response function ranging over a cone. The elements of each cone are completely characterized by an integral representation. The 1:1 correspondence between the viscoelastic response functions is expressed in terms of cone-preserving mappings and their inverses. The theory covers scalar- and tensor-valued viscoelastic response functions.


2012 ◽  
Vol 12 (01) ◽  
pp. 1250140
Author(s):  
GEORGY P. EGORYCHEV ◽  
FERIDE KUZUCUOĞLU ◽  
VLADIMIR M. LEVCHUK

Using the method of integral representation of combinatorial sums we enumerate ideals of certain nilpotent matrix rings.


Author(s):  
Giovanni Di Fratta

The objective of this paper is to present a modern and concise new derivation for the explicit expression of the interior and exterior Newtonian potential generated by homogeneous ellipsoidal domains in R N (with N ≥3). The very short argument is essentially based on the application of Reynold's transport theorem in connection with the Green–Stokes integral representation formula for smooth functions on bounded domains of R N , which permits to reduce the N -dimensional problem to a one-dimensional one. Owing to its physical relevance, a separate section is devoted to the the derivation of the demagnetizing factors of the general ellipsoid which are one of the most fundamental quantities in ferromagnetism.


The flow of a viscous fluid at small Reynolds numbers (Stokes flow) in a three-dimensional formulation is investigated. In this case, the inertial terms in the equations of motion can be neglected. Such flows can occur in nanotubes that can be considered as inclusions in representative volume elements of nanomaterials. By using the fundamental solution of Ossen, an integral representation of the velocity is proposed. This representation is used to receive an integral equation for an unknown density. The solution of the resulting equation makes it possible to calculate the fluid pressure on the walls of the shell. The case of axially symmetric flows is investigated. For this, an integral representation of the unknown velocity in cylindrical coordinates is obtained. By integrating over the circumferential coordinate, the two-dimensional singular integral equation is reduced to one-dimensional one. It has been proved that the components of the kernels in singular operators are expressed in terms of elliptic integrals of the first and second kind. It has been proved that the singularities of the kernels of one-dimensional singular integral equations have a logarithmic character. To calculate elliptic integrals, the Gaussian algorithm based on the use of the arithmetic-geometric mean value is proposed. This procedure allows us to obtain logarithmic singular components with high accuracy, which makes it possible to use special quadrature formulas to calculate such integrals. An algorithm with usage of the boundary element method for the numerical solution of the obtained singular integral equations is proposed. The method for solving one-dimensional singular equations, where the kernels contain elliptic integrals with logarithmic singularities (i.e logarithmic singularity is not expressed explicitly) has been tested. The obtained numerical results have been compared with the well-known analytical solutions. The data obtained indicate the high efficiency of the proposed numerical method.


1997 ◽  
Vol 11 (18) ◽  
pp. 785-793
Author(s):  
M. E. Fouladvand ◽  
A. S. Khorashad

The method of Discretized Path Integral Representation (DPIR) is used to convert the one-dimensional quantum Z3 Potts chain into a two-dimensional classical Interaction-Round a Face (IRF) model. Then we use the Double-Chain approximation to obtain the free energy and thermodynamic properties of the model.


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