University of Piteti

Romania

University of Piteti

Romania
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Cpn A.,Romanian Academy of Sciences | Ene H.,Romanian Academy of Sciences | Ene H.,University of Piteti | Paa G.,Romanian Academy of Sciences | And 3 more authors.
Nonlinear Analysis, Theory, Methods and Applications | Year: 2011

The purpose of this paper is to propose and study a mathematical model and a boundary control problem associated to the miscible displacement of hydrogen through the porous anode of a PEM fuel cell. Throughout the paper, we study certain variational problems with a priori regularity properties of the weak solutions. We obtain the existence of less regular solutions and then we prove the desired regularity of these solutions. We consider a control problem that permits to determine the boundary distribution of the pressure which provides an optimal configuration for the temperature and for the concentration, as well. Since the solution of the problem is not unique, the control variable does not appear explicitly in the definition of our cost functional. To overcome this difficulty, we introduce a family of penalized control problems which approximates our boundary control problem. The necessary conditions of optimality are derived by passing to the limit in the penalized optimality conditions. © 2010 Elsevier Ltd. All rights reserved.


Tabacu S.,University of Piteti | Parlac S.,University of Piteti | Tomus C.,University of Piteti | Baba V.,University of Piteti
International Journal of Crashworthiness | Year: 2012

This paper presents methods that can be used to connect and transfer the numerical model from structural applications to moulding analysis. Once moulding numerical analysis is performed stress and strain data are exported to be used as initial conditions for the structural analysis. Also a random distribution of the thickness is embedded into the computational model. The material model makes an important contribution to the quality and reliability of the simulation results and each simulation model was evaluated for different material models. Numerical results are compared with experimental data and a score is assigned to the computational models presented in this study. For the first case, the numerical model includes the fixture according to the experiment while a second case is focused on the stand alone model of the cockpit model. By defining a collaborative simulation that uses manufacturing process results, or using codes that can help solving some uncertainties of the model (random thickness) structural analysis becomes more reliable and may provide accurate results that are in good agreement with measured experimental data. © 2012 Copyright Taylor and Francis Group, LLC.


MacArie V.M.,University of Piteti | Breaz D.,Decembrie University
Computers and Mathematics with Applications | Year: 2011

The main object of the present paper is to discuss some extensions of certain integral operators and to obtain their order of convexity. Several other closely related results are also considered. © 2011 Elsevier Ltd. All rights reserved.

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