Search results for "Simultaneous equations"

Systematic Approach To Calculate the Concentration of Chemical Species in Multi-Equilibrium Problems

2010

A general systematic approach is proposed for the numerical calculation of multi-equilibrium problems. The approach involves several steps: (i) the establishment of balances involving the chemical species in solution (e.g., mass balances, charge balance, and stoichiometric balance for the reaction products), (ii) the selection of the unknowns (the concentration of selected chemical species at equilibrium), (iii) the estimation of the concentration of the other species based on the selected species and the equilibrium expressions, and (iv) the minimization of the sum of the squared balances (search of the optimal combination of the unknowns). The application of the systematic approach to cas…

Exact Solutions of the Two Dimensional Boussinesq and Dispersive Water Waves Equations

2010

In this paper two-dimensional Boussinesq and dispersive water waves equations are investigated in exact solutions. The Exp-function method is used for seeking exact solutions of the equations through symbolic computation.

Comparison results for Monge - Ampère type equations with lower order terms

2003

In this paper we deal with Monge-Ampère type equations in two dimensions and, using the symmetrization with respect to the perimeter, we prove some comparison results for solutions of such equations involving the solutions of conveniently symmetrized problems.

Qualitative Theory of Differential Equations, Difference Equations, and Dynamic Equations on Time Scales

2016

We are pleased to present this special issue. This volume reflects an increasing interest in the analysis of qualitative behavior of solutions to differential equations, difference equations, and dynamic equations on time scales. Numerous applications arising in the engineering and natural sciences call for the development of new efficient methods and for the modification and refinement of known techniques that should be adjusted for the analysis of new classes of problems. The twofold goal of this special issue is to reflect both the state-of-the-art theoretical research and important recent advances in the solution of applied problems.

On new ways of group methods for reduction of evolution-type equations

2005

AbstractNew exact solutions of the evolution-type equations are constructed by means of a non-point (contact) symmetries. Also we analyzed the discrete symmetries of Maxwell equations in vacuum and decoupled ones to the four independent equations that can be solved independently.

On the Sets of Regularity of Solutions for a Class of Degenerate Nonlinear Elliptic Fourth-Order Equations with L1 Data

2007

We establish Holder continuity of generalized solutions of the Dirichlet problem, associated to a degenerate nonlinear fourth-order equation in an open bounded set , with data, on the subsets of where the behavior of weights and of the data is regular enough.

A new result on impulsive differential equations involving non-absolutely convergent integrals

2009

AbstractIn this paper we obtain, as an application of a Darbo-type theorem, global solutions for differential equations with impulse effects, under the assumption that the function on the right-hand side is integrable in the Henstock sense. We thus generalize several previously given results in literature, for ordinary or impulsive equations.

Oscillation criteria for even-order neutral differential equations

2016

Abstract We study oscillatory behavior of solutions to a class of even-order neutral differential equations relating oscillation of higher-order equations to that of a pair of associated first-order delay differential equations. As illustrated with two examples in the final part of the paper, our criteria improve a number of related results reported in the literature.

Nonlinear Functional Difference Equations with Applications

2013

Testing of a constitutive equation for entangled networks by elongational and shear data of polymer melts

1973

An entangled network such as a polymer melt or a concentrated solution is here described by a set of two simultaneous equations. One of them is a balance of entanglements, the other gives the stress in the classical form of aMaxwell equation.