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.
Extensive studies have been conducted on the microbial properties of Streptococcus pneumoniae all over the world ,but there are few studies in Iraq on the most important factors of virulence possessed by S.pneumoniae isolates found in Iraq , 195 of sputum specimens were collected from patients with pneumonia acquired from the community who were clinically diagnosed by specialized doctors depending on symptoms and Radiography of Chest . Eighteen isolates of S.pneumoniae were diagnosed by special traditional methods that used in the phenotypic identification . All isolates 18 (100%) have been given positive results for the optochin test , bile solubility test
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This research was to provide a definition of quality, dimensions and concepts, whether traditional or modern concept, as well as review the dimensions of quality in higher education and vision and mission with the overall objectives of the Statistics Department.
After reviewing quality goals and purposes achieved as well as the mechanisms used to achieve them. and use standard Six-Sigma as one of the methodologies used in quality with the historical roots of using this methodology and methods applied and their definitions t
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This study aims at identifying the impact of the application of IFRS 15 "Revenue from contracts with customers on the quality of financial reporting, through application to faculty members in the accounting departments of Iraqi universities and auditors. The problem of the study was the multiplicity of accounting rules and standards Which deals with the issues of revenue recognition , as well as the lack of consistency of most of them with the common framework of financial accounting, which results in low quality of financial reporting in the current financial statements, where the formulation of one hypothesis was the lack of relationship of significant significance The application of IFRS 15 "Recognition of rev
... Show MoreThe electoral mechanism is remarkably clear, a political tool for institutional construction, directing political life, forming the political scene, and forming the partisan scene. This process was through the design of electoral laws, as elections in Tunisian political history represented the indicator of its slow and accelerated transformations, so The elections in Tunisia usually coincide with important political stages, accompanied by legislative or constitutional amendments in general, Islamic or secular forces have played a fundamental role in promoting the democratic experience and the principle of the peaceful transfer of power. This led to the formation of a national consensus that would help the country not enter into political
... Show MoreEffects of Boron on the structure of chloroplasts membrane isolated from cauliflower are investigated , using light scattering technique. Results obtained in this study suggest that Boron in the concentration range (0.1-5 µm) can fluidize the lipids of the chloroplast membrane due to different extent. Mechanisms by which Boron can change the lipid fluidity is discussed. Furthermore, an experimental evidence is presented to show that2µM Boron can mediate conformational changes in the membrane –bound proteins of the cauliflower’s chloroplast.
The study aimed to identify what (isis) (Daesh) have been touched in the opening article of Al-Nabaa newspaper This objective is organized for asset of sub-targets it is the knowledge of media discourse and for those who are directed and methods of employing the strong content debt organization and we used the survay method to monitor and understand the content of opening anticale and the researcher took the numbers of the newspaper for years 2015-2018 consist of 157 The results of this study are :
* Use religious texts from (Holly qoran) (Abbreission of the prophetic) Remove from its context and empby them in justifying in what use of vio |
The political struggle being waged by Muslims today is one of the most important issues that have preoccupied the Arab and international media, and the failures that have afflicted Muslims in our contemporary world have negatively affected the younger generations and led them, and with the influence of anti-Islam media, to rely on accusing Islam as a religion with all the negative in Islamic and Arab society . So secularism took its role in spreading these concepts by deviating from its course from the concept of science to the concept of (the religion).
From here the calls for reform rose to return the Muslims to the incubator of Islam, so people turned around them, but they turned into competing Islamic polit
The performance of a diesel engine was tested with diesel oil contaminated with glycol at the engineering workshop/Department of Agricultural Machines and Equipment / College of the Agricultural Engineering Sciences at the University of Baghdad. To investigate the impact of different concentrations of glycol on the performance of a diesel engine, an experimental water-cooled four-stroke motor was utilized, with oil containing 0, 100, and 200 parts per million (ppm). Specific fuel consumption, thermal efficiency, friction power, and exhaust gas temperature were examined as performance indicators. To compare the significance of the treatments, the study employed a full randomization design (CRD), with three replicates for each treatment at th
... Show MoreThe organizational culture is an effective control mechanism that dictates the behavior of employees and according to their intellectual and social orientations, so it is considered a more powerful way to control employee orientations and determine their management according to organizational rules and regulations, as it was one of the most important factors determining the performance of organizations, while organizational performance is a measure of what the organization has achieved from the objectives of the scheme To ensure that it faces various changes and remains within the global competition, and to reach that it was necessary to identify the most prominent and most important research problems in knowing the extent of com
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