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The purpose of this paper is to investigate the steady flow of a non‐Newtonian power‐law type fluid over a permeable stretching surface. The surface is stretched with a prescribed skin velocity following a power‐law variation along its length.

Using appropriate similarity variables and boundary layer approximations, the continuity and momentum equations are reduced to an ordinary differential equation subject to appropriate transformed boundary conditions, with three dimensionless parameters: the power‐law index of the non‐Newtonian fluid, suction/injection parameter and the power law index of the skin velocity. These equations are solved numerically by using the fourth‐order Runge‐Kutta integration algorithm coupled with a conventional shooting procedure. Comparisons with closed form analytical solutions obtained for the case of Newtonian fluid by previous authors are also performed.

It was found that the dimensionless entrainment velocity decreases with the power exponent m, of the prescribed skin velocity, irrespective of the non‐Newtonian fluid nature, for both impermeable and permeable surfaces. Large rates of injection lead to very large values of the skin friction, the effect being more intense for small values of the dimensionless flow index n. At the same rate of the injection/suction, the skin friction S is increased when the surface is stretched linearly than uniformly.

This type of problem has potential to serve as a prototype for many manufacturing processes such as rolling sheet drawn from a die, cooling and/or drying of paper and textile, manufacturing of polymeric sheets, sheet glass and crystalline materials, etc.

A thorough analysis of the hydrodynamics of a stretching surface is performed in the present paper, by combining analytical and numerical means. The topics covered here (Ostwald‐de Waele power‐law fluid + prescribed skin velocity + permeability of the stretching surface) seem to be not reported till now in the literature.

The research attempts to aim to evaluate the perception that different stakeholder groups have of one of the largest and most important Romanian university with respect to its sustainability orientation. The exploratory empirical research reveals some important aspects which must be closely pursued and properly implemented by the management of the university to further develop sustainability strategies. The paper offers a novel approach regarding the way a university can and must focus on different specific measures on sustainability to gain a better position on the educational market, to attract new students and lifelong learning (LLL) programme participants, as well as to become a trend setter for defining and transferring good practices within the society.

Data were collected by questionnaires and in-depth-interview guides which were distributed to different stakeholder groups: bachelor (undergraduate) and master’s students versus LLL programme participants coming from different high schools across the country enrolled on a training course organized by the university and high school principals versus staff members of the university holding coordination and/or management positions. The collected data were then analyzed by means of econometric analysis. Data validity, reliability and internal consistency were checked (Cronbach’s α coefficient, “item-to-total” correlation, the KMO criterion (>0.7) and Bartlett’s test of sphericity). With the help of exploratory factor analysis, the way in which different stakeholders value and perceive the specific measures and efforts undertaken by the university has been extracted.

Students, LLL participants and members of the university staff perceived the university’s positive orientation towards sustainability and the measures taken in this respect. All stakeholders expressed highly favourable opinions of the university’s dealings with different sustainability aspects, such as its attitude towards its employees, its performance within the higher education market and its establishment of an attractive and innovative educational programme, in compliance with sustainability principles, environmental protection and modern attitudes towards society.

The research has been conducted on a sample of students of bachelor and master level, belonging to the biggest faculty of the university (as to number of students and staff). In a more comprising study, the focus should also be on bachelor, master and PhD students of the other faculties of the university, as well as on citizens of the community or in general on people from Transylvania and/or Romania. The university under investigation is one of the most important employers of the region. Further dimensions of sustainable development could also be pursued in a future study.

The university shows an orientation towards civil society by means of specific actions and programs. The university supports and takes part in the organization of cultural and artistic events in cooperation with local authorities and other cultural and/or social institutions and organizations. Respondents also refer to some examples of best practices that might be applied by education institutions to educate young people towards developing a proper sustainable mentality.

There exist almost no comparative empirical studies of sustainability on Romanian universities that take account of the perspectives of students, LLL participants and staff members. The findings have a high potential in developing a proper strategy for the university involved but could also be used by the government if designing a national wide policy regarding this issue. Different authors argue that young people are more conscious about sustainability, organic stuff, environmental protection, green marketing, etc. Taking into consideration the sensitivity of young peoples (students, staff members, etc.), as well as the fact that the university establishes social trends, the idea of studying sustainability in a university could be regarded as a novelty approach.

The purpose of this paper is to theoretically study the problem of mixed convection boundary layer flow and heat transfer past a vertical needle with variable wall temperature using nanofluids. The similarity equations are solved numerically for copper nanoparticles in the based fluid of water to investigate the effect of the solid volume fraction parameter of the fluid and heat transfer characteristics. The skin friction coefficient, Nusselt number, and the velocity and temperature profiles and are graphically presented and discussed.

The transformed system of ordinary differential equations was solved using the function bvp4c from Matlab. The relative tolerance was set to 1e-10. For the study of the stability the authors also used the bvp4c function in combination with chebfun package from Matlab.

It is found that the solid volume fraction affects the fluid flow and heat transfer characteristics. The numerical results for a regular fluid and forced convection flow are compared with the corresponding results reported by Chen and Smith. The solutions exists up to a critical value of λ, beyond which the boundary layer separates from the surface and the solution based upon the boundary-layer approximations is not possible

The paper describes how multiple (dual) solutions for the flow reversals are obtained. A stability analysis for this flow reversal has been also done showing that the lower solution branches are unstable, while the upper solution branches are stable.

The purpose of this paper is to present an analytical study on an unsteady magnetohydrodynamic (MHD) boundary layer flow of a rotating viscoelastic fluid over an infinite vertical porous plate embedded in a uniform porous medium with oscillating free-stream taking Hall and ion-slip currents into account. The unsteady MHD flow in the rotating fluid system is generated due to the buoyancy forces arising from temperature and concentration differences in the field of gravity and oscillatory movement of the free-stream.

The resulting partial differential equations governing the fluid motion are solved analytically using the regular perturbation method by assuming a very small viscoelastic parameter. In order to note the influences of various system parameters and to discuss the important flow features, the numerical results for fluid velocity, temperature and species concentration are computed and depicted graphically vs boundary layer parameter whereas skin friction, Nusselt number and Sherwood number at the plate are computed and presented in tabular form.

An interesting observation is recorded that there occurs a reversal flow in the secondary flow direction due to the movement of the free stream. It is also noted that a decrease in the suction parameter gives a rise in momentum, thermal and concentration boundary layer thicknesses.

Very little research work is reported in the literature on non-Newtonian fluid dynamics where unsteady flow in the system arises due to time-dependent movement of the plate. The motive of the present analytical study is to analyse the influences of Hall and ion-slip currents on unsteady MHD natural convection flow of a rotating viscoelastic fluid (non-Newtonian fluid) over an infinite vertical porous plate embedded in a uniform porous medium with oscillating free-stream.

The purpose of this paper is to study the effects of chemical reaction, thermal radiation and Soret and Dufour effects of heat and mass transfer by natural convection flow about a truncated cone in porous media.

The problem is formulated and solved numerically by an accurate implicit finite-difference method.

It is found that the Soret and Dufour effects as well as the thermal radiation and chemical reaction cause significant effects on the heat and mass transfer charateristics.

The problem is relatively original as it considers Soret and Dufour as well as chemical reaction and porous media effects on this type of problem.

The purpose of this paper is to numerically solve the problem of steady mixed convection boundary layer flow past a vertical flat plate embedded in a fluid-saturated porous medium filled by a nanofluid. The non-Darcy equation model along with the mathematical nanofluid model proposed by Tiwari and Das (2007) has been used.

Using appropriate similarity transformations, the basic partial differential equations are transformed into ordinary differential equations. These equations have been solved numerically for different values of the nanoparticle volume fraction, the mixed convection and the non-Darcy parameters using the bvp4c function from Matlab. A stability analysis has been also performed.

Numerical results are obtained for the reduced skin-friction, heat transfer and for the velocity and temperature profiles. The results indicate that dual solutions exist for the opposing flow case (λ<0). The stability analysis indicates that for the opposing flow case, the lower solution branch is unstable, while the upper solution branch is stable. In addition, it is shown that for a regular fluid (φ=0) a very good agreement exists between the present numerical results and those reported in the open literature.

The problem is formulated for three types of nanoparticles, namely, copper (Cu), alumina (Al₂O₃) and titania (TiO₂). However, the paper present results here only for the Cu nanoparticles. The analysis reveals that the boundary layer separates from the plate. Beyond the turning point it is not possible to get the solution based on the boundary-layer approximations. To obtain further solutions, the full basic partial differential equations have to be solved.

Nanofluids have many practical applications, for example, the production of nanostructured materials, engineering of complex fluids, for cleaning oil from surfaces due to their excellent wetting and spreading behavior, etc.

Nanofluids could be applied to almost any disease treatment techniques by reengineering the nanoparticle properties.

The present results are original and new for the boundary-layer flow and heat transfer past a vertical flat plate embedded in a porous medium saturated by a nanofluid. Therefore, this study would be important for the researchers working in porous media in order to become familiar with the flow behavior and properties of such nanofluids.

The purpose of this paper is to study the effects of chemical reaction on mixed convection flow along a sphere in non‐Darcian porous media.

The sphere surface is maintained at uniform temperature and species concentration for both cases of heated (assisting flow) and cooled (opposing flow) sphere. An appropriate transformation is employed and the transformed equations are solved numerically using an efficient implicit iterative tri‐diagonal finite difference method.

It is found that chemical reactions have significant effect on heat and mass transfer. Comparisons with previously published work are performed and the results are found to be in excellent agreement.

The paper is original and describes how a parametric study of the physical parameters was conducted and illustrates graphically a representative set of numerical results for the velocity, temperature, and concentration profiles, as well as the local skin‐friction coefficient, local wall temperature, and local wall concentration, to show interesting features of the solutions.

The purpose of this work is to study the flow of mixed convection and mass transfer of a steady laminar boundary layer about an isothermal vertical flat plate embedded in a non‐Darcian porous medium in the presence of chemical reaction and viscous dissipation effects.

The governing partial differential equations are converted into ordinary differential equations by similarity transformation, which are solved numerically by employing the fourth‐order Runge‐Kutta integration scheme with Newton‐Raphson shooting technique.

It was found that the local Nusselt number was predicted to decrease as either of the chemical reaction parameter or the Eckert number increased. On the other hand, the local Sherwood number was predicted to increase as a result of increasing either of the chemical reaction parameter or the Eckert number. Also, in the absence of viscous dissipation, both the local Nusselt and Sherwood numbers increased as the mixed convection increased.

The paper illustrates chemical reaction and viscous dissipation effects on Darcy‐Forchheimer mixed convection in a fluid saturated porous media.

The purpose of this paper is to study the Blasius flat plate with viscous dissipation in the presence of suction or injection effects in the boundary layer of a viscoelastic fluid.

The governing partial differential equations are derived as a first order ordinary differential equation using similarity (Blasius) variables. Velocity profiles, temperature profiles, skin friction parameters, and heat transfer parameters are computed numerically for various values of the viscoelastic parameter K, the suction or injection parameter f _w, the Prandtl number Pr, the Eckert number Ec, and the moving parameter λ.

The effects of the viscoelastic, moving, and suction/injection parameters on the skin friction and heat transfer of the flat plate are studied. The effects of these parameters on the velocity and temperature profiles are also presented for 0≤Pr≤3.

To the best of the authors' knowledge, this important classical problem has not been studied before for the case of a viscoelastic fluid. Thus, the results are original and new for this type of fluid.

The purpose of this paper is to consider heat and mass transfer by natural convection from a vertical cylinder in porous media for a temperature‐dependent fluid viscosity in the presence of radiation and chemical reaction effects.

The governing equations are transformed into non‐similar differential equations and then solved numerically by an efficient finite‐difference method.

It is found that there are significant effects on the heat and mass transfer characteristics of the problem due to the variation of viscosity and radiation and chemical reaction effects.

The paper combines the effects of radiation, chemical reaction, non‐Darcy porous media effects along with the variation of viscosity with temperature.