The BEK family of flows have many important practical applications such as centrifugal pumps, steam turbines, turbo-machinery and rotor-stator devices. The Bödewadt, Ekman and von Kármán flows are particular cases within this family. The convective instability of the BEK family of rotating boundary-layer flows has been considered for generalised Newtonian fluids, power-law and Carreau fluids. A linear stability analysis is conducted using a Chebyshev collocation method in order to investigate the effect of shear-thinning and shear-thickening fluids for generalised Newtonian fluids on the convective Type I (inviscid crossflow) and Type II (viscous streamline curvature) modes of instability. The results reveal that shear-thinning power-law fluids have a universal stabilising effect across the entire BEK family of flows. However, the convective instability characteristics for the shear-thinning and shear-thickening Carreau fluids are affected by the value of the relaxation parameter k. The results reveal that Shear-thinning Carreau fluids have a small destabilising effect, while shear -thickening fluids have a slight stabilising effect on the Type I and Type II mode for the BEK family of flows when k =100. On the other hand, shear-thinning and shear-thickening Carreau fluids are found to have stabilising and destabilising effect, respectively for optimal relaxation value ko. The results are presented in terms of neutral curves and growth rates. Furthermore, an energy analysis is presented to gain insight into the underlying physical mechanisms behind the stabilising effects of generalized Newtonian fluids. In conclusion, the use of shear-thinning power-law and Carreau fluids with optimal value ko can be recommended to reduce skin-friction drag in enclosed rotor-stator devices for the entire BEK family of flows.
Mosques could be considered as one of the most powerful architectural types throughout historical ages. With their highly symbolic formal legacy, Mosques play an essential role in providing the Islamic city with its special identity. Nevertheless, the advent of digital technology and its ubiquity at different levels of architectural design marked the emergence of new tendencies in the Architecture of Mosques, represented by various models added to the storage of this architectural type. Consequently a review of these tendencies would be needed, aiming at pointing out the formal transformations and new suggested characteristics.
The paper investigates the surviving and the disappearing formal components of&n
... Show MoreCold atmospheric plasma (CAP) is used widely in medical and biological fields because of non-thermal effected. Direct application of plasma is preferred in medical functions, so, direct application of cold plasma has obtained by the floating electrode dielectric barrier discharge (FE-DBD) system. The purpose of this paper to review the effect of (CAP) on the reproductive hormones (testosterone, LH, E2, progesterone, for male rats. The study appeared that no significant effect on E2 and progesterone hormone for all time of exposure, besides this significant difference in LH hormone (P<0.05) at 15 sec, (P<0.0001) at 30, 90 sec and (P<0.001) at 60 sec of exposure to plasma. Added to that significant difference (P<0.01) at 15, 30, 60 sec and no
... Show MoreThe CdSe pure films and doping with Cu (0.5, 1.5, 2.5, 4.0wt%) of thickness 0.9μm have been prepared by thermal evaporation technique on glass substrate. Annealing for all the prepared films have been achieved at 523K in vacuum to get good properties of the films. The effect of Cu concentration on some of the electrical properties such as D.C conductivity and Hall effect has been studied.
It has been found that the increase in Cu concentration caused increase in d.c conductivity for pure CdSe 3.75×10-4(Ω.cm)-1 at room temperatures to maximum value of 0.769(Ω.cm)-1 for 4wt%Cu.All films have shown two activation energies, where these value decreases with increasing doping ratio. The maximum value of activation energy was (0.319)eV f
The primary objective of this study was to identify the obstacles and problems encountered in the work of sports clubs according to the reality of the application of administrative automation. The present study was conducted in the sports club headquarters of Baghdad within the timeframe of October 2021 to December 2021. In the present study, a descriptive approach was used by the researchers in an analytical style according to the nature of the problem to be studied. The research community of the current study was composed of 100 sports clubs in the governorate of Baghdad. A total of 80 questionnaires were filled by the sample participants, who represented a percentage of 80% of the research community. After processin
... Show MoreGeographical, economic, historical, environmental and security factors play a role in strengthening the drive towards union, as well as addressing the need to express regional and federal identity. This is a clear example of this tendency. One legal or one political system with the parts of this united personality retaining their privacy and identity, and there is a delegation to the central entity of the union with some of the common powers while retaining some powers for these parts or states, which means the availability of autonomy for the constituent states of the union and this is the most important characteristic of the federal states or federations It is the autonomy of each state or country participating in the union. Accordingly,
... Show MoreThe training of great importance in the play, in building optic and intellectual broadcast codes tags, and then comes after the recipient at the reception of such codes and decoded tags, and is the rhythm, the color of the most important elements of configuration, consistent with other elements, Kaltmathl, and focus, and harmony, and dissonance
Language is fundamental and important for the development of various skills especially in the kindergarten stage where the child begins to approach others and interact with them linguistically listen to them and make sentences to communicate his ideas to them and without the ability to talk and expression, the child's benefit of his experiences in the kindergarten remains limited.
And that children at any stage of early education are subject to different stages of linguistic development, and these stages are a fundamental feature in learning, especially for the skills of speaking, listening and reading, Therefore, the researcher chose the speaking skill the
... Show MoreIt is important to set the background of stiffen arbitration agreement, to understand the real reasons of the fighting. When the Syrians began to lose, raised the masahif and made their announcement, most the qurrar, and so no need to continued fighting.
In their view all that remained was the matter of drawing up formal peace with Ali, Muamiya; Ali would recognize as Amir al-muminin by both Syrian and Iraqis.
The most of the Iraqisfavored settlement for different persons, for example-A'shath, the most power full of the clan leaders of Rabia, his interest by insuring that neither Ali nor Mu
... Show MoreAs an architectural philosophical concept, Islamic architecture cannot be considered arches, doors, domes and lighthouses, since Islamic architecture is based on a structural system of religious, mental, philosophical and logical origins and beliefs shared by the arts, technology and the requirements of the surrounding environment. Rather, the architectural designer's distance from it becomes as if it is for people not from this world, and Islamic architecture is not abbreviated on the heritage side as much as it is a renewed "modern" state, dealing with the concepts of Islam that are valid for every time and place. This can be seen through the mechanisms that produced heritage architecture and what was built on it, which is not a simula
... Show MoreEducation represents a different their areas, especially after the educational cornerstone of Staff of the community in which young person’s that can stand up and shared the overall development process.
In order for education to be effective in the community, there is a need to develop to cope with the process development of civilization and modern technology. And for that to be achieved the goal of current research to stand on the advancement of the educational process through Knowledge of educational strategies that had previously requirements put forward for the development of educational process as well as through Knowledge of the mo
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