مجله بین المللی ریاضیات صنعتی
سال:1396 | دوره:9 | شماره:2 |تعداد مقالات:9

The combined e ects of magnetic field, Navier slip and convective heating on the entropy generation in a flow of a viscous incompressible electrically conducting fluid between two infinite horizontal parallel plates under a constant pressure gradient have been examined. Both the lower and upper plates of the channel are subjected to asymmetric convective heat exchange with the ambient fluid.The governing non-linear governing partial differential equations are solved using the MATLAB PDE solver. The entropy generation number and the Bejan number are also obtained. The influences of the pertinent flow parameters on velocity, temperature, entropy generation and Bejan number are discussed graphically. It is observed that the plate surfaces act as a strong source of entropy generation and heat transfer irreversibility. Also, the entropy generation number decreases for increasing values of the magnetic parameter. The slip parameters are found to control the entropy generation. By using asymmetric cooling of the plates, it is possible to operate the system with reduced entropy generation rate.

The importance of Problem Solving (PS) has been realized for such a long time that in a direct or indirect way affects our daily lives in many ways. Assessment cases appear frequently for PS skills which involve a degree of uncertainty and (or) ambiguity. Fuzzy logic, due to its nature of characterizing such cases with multiple values, offers rich resources for dealing with them. On the other hand, Fuzzy Numbers (FNs) play a fundamental role in fuzzy mathematics, analogous to the role played by the ordinary numbers in classical mathematics. In the present paper we utilize the two simplest forms of them, i.e. the Triangular and Trapezoidal FNs, together with the Centre of Gravity (COG) defuzzication technique as assessment tools for PS skills. Our results are illustrated by three examples in which the assessment outcomes of FNs are validated through their comparison with the corresponding outcomes of assessment methods of the bi-valued and fuzzy logic already tested in author's earlier works.