Vol 28, No 2 (2017)

The article considers the inverse boundary-value problem of heat conduction which involves determining the time distribution of temperature on the boundary given the spatial distribution of the temperature at the final time instant. The problem is reduced to an integral equation of the first kind with a symmetrical kernel. The integral equation is solved by a special iterative method. Test examples demonstrate convergence and stability of the proposed method.

The article discusses the development of noninvasive preoperative methods for the localization of eloquent areas in the human brain. The accuracy with which such areas are localized directly determines the outcome of surgery. An analytical formula is derived for the solution of the forward problem that computes the magnetic field on the surface of the head from the known location and orientation of a current dipole in the low-frequency approximation in the spherical model. The inverse problem is also solved, reconstructing the location and orientation of the source given the magnetic field on the surface of the head. Qualitative analysis of the ellipsoidal model is carried out.

Numerical methods for modeling the behavior of an industrial aluminum electrolyzer are investigated and developed. Solving a prototype problem that brings out the specific features of aluminum electrolysis, we compare two approaches to investigating the relaxation of oscillations in an electrolyzer with a free boundary between the phases. The first approach is the classical finite-difference method while the second approach uses smoothed particle hydrodynamics (SPH). The SPH method had not been applied previously to model aluminum electrolysis and it required development in this context. In particular, a new algorithm was proposed for one of the SPH subproblems that allowed for the dependence of acceleration on the velocity. The computational characteristics and the accuracy of the two methods are compared for the relaxation of free interface oscillations. The strengths and weaknesses of the two methods are discussed, as well as their potential for applications. It is shown that SPH is applicable to more realistic three-dimensional problems, such as real-time feedback control of aluminum electrolysis that can ensure online prevention of the onset of MHD instability.

A three-dimensional problem for a homogeneous isotropic thermoelastic half-space solids with temperature-dependent mechanical properties subject to a time-dependent heat sources on the boundary of the half-space which is traction free is considered in the context of the generalized thermoelasticity with dual-phase-lag effects. The normal mode analysis and eigenvalue approach techniques are used to solve the resulting non-dimensional coupled field equations. Numerical results for the temperature, thermal stresses and displacement distributions are represented graphically and discussed. A comparison is made with the result obtained in the absence of the temperature dependent elastic modulus. Various problems of generalized thermoelasticity and conventional coupled dynamical thermoelasticity are deduced as special cases of our problem.

A new method for seismic data processing is considered. Surface traveling waves are recovered from these data and wave-dependent coefficients are determined. The results of the proposed method are consistent with the results reported by other Chinese researchers [4, 5].

This paper is concerned with the problem of determining the approximate solution of real definite integrals by means of the mixed quadrature rule, which has been implemented with the quasi-type singular integral of electromagnetic field problems. The main advantage of the proposed numerical integration method over electromagnetic field problems is its efficiency, less functional evaluation and simple applicability. Five test numerical examples are provided to compare the accuracy with other researchers.

The optical theorem is generalized to the case of excitation of a local body by a multipole. To compute the extinction cross-section, it is sufficient to find the derivatives of the scattered field at the single point where the multipole is located. The relationship obtained in this article makes it possible to test software modules developed for studying wave diffraction on transparent bodies.

The Gross–Pitaevskii equation is at the core of the mathematical problem of the propagation of a Bose–Einstein condensate (BEC). In this article, we look for an analytical soliton solution in the three-dimensional Gross–Pitaevskii equation. We compare our analytical solution with the various numerical soliton solutions (dark solitons, light solitons, reflected solitons) reported by many researchers for the case of BEC interacting with an external potential (an obstacle, a magnetic trap, etc.). Our analytical solution can be applied to find both the main and the reflected soliton solution.