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.
The current research aims to diagnose the role of social responsibility as a contributing factor in enhancing the quality of services provided by the public sector in Iraq, where the research sought to demonstrate the relationship and impact of social responsibility dimensions (economic, legal, moral, and human) on the sector Services related to the electric field in Nineveh governorate because of its importance and its direct relationship with the citizen especially after the end of military operations in the destruction of the electricity sector by a large percentage in the city of Mosul. Nineveh Electricity Distribution Directorate / Center was chosen as a research community including (administrators and staff) of the research
... Show MoreExpected to The organizational commitment by employees increases their loyalty towards their organization and thus contribute to enhancing their performance , therefore this study aimed to discover the relationship and the impact between the organizational commitment (emotional commitment, standard commitment, continuous commitment) and the performance of employees in the company researched, additional to know the available organizational commitment levels of employees in the company researched and its impact on the performance of employees, Research was conducted at the General Company for products in the dairy to achieve the goals of research has been developed questionnaire conation (22 ) items to collect data from the study s
... Show MoreThe current study aims to overcome the conflicts facing the company in its way of staying and continuing to maintain its performance excellent in light of the intense competition, which made it seek to find strong ways and links with its customers through electronic communication using electronic platforms, and this put confidence and safety in The place of suspicion and fear of not fulfilling credibility or violating the privacy, so this research comes to answer about the question: “Can the company achieve an excellent performance by relying on the customer's electronic confidence?”.
The study followed the descriptive and analytical approaches by providing a virtual model and testing the zero hypotheses, which stipulat
... Show MoreThis study included an analysis of three stations (Al Dora, Al Za'franiya, and Arab Ejbur) chosen to study the Physiochemical and microorganism (Fungi and Bacteria) loud of the Tigris River in the southern section of Baghdad city. The result of this research shows that the highest temperature recorded in summer in Al Za'franiya was 37Co, while the lowest temperature recorded in winter in Al Dora was 9Co. and the value of pH recorded the highest in summer it was 7.9 in Arab Ejbur, and the lowest value was in winter 7.1 in Al Dora regions, While Total Organic Carbon (TOC) shows the highest values found in the summer was 6.7 Mg L-1in Al Za'franiya Samples, and the lowest values were 2.0 Mg L-1in Arab Ejbur during the winter. The more f
... Show MoreThe volatility of the financial markets and the oil market plays a major role in influencing macroeconomic activity, as well as the high interaction between the both markets and the remarkable sensitivity to their each other fluctuations which cause the undesirable impact on other economic sectors as an expected result due the mentioned interaction.
The study aimed to analyze the relationship between the volatility of the major US market indices represented by the DJIA index, S & P500, due to their comprehensiveness of the financial market, as they summarize the performance of the entire US market which is the largest economy in the world, as well as the difference in the calculation mechanism, and oi
... Show MoreThe first chapter the importance of research and need for education scientists see that the roots of the use of a specimen Wheatley in learning and teaching back to Grayson Wheatley, one of the largest supporters of a modern construction, which lay the groundwork for the specimen stage and the form in which it is. That was attributed to him, often called his name called while some educators based learning strategy on the issue. He sees the learner in this model make him a meaningful understanding of problems during his progress, thereby acting with his colleagues to find solutions to them in small groups. He
Borders Search: Search by students is determined by th
... Show MoreThis study investigated the effect of using brainstorming as a teaching technique on the students’ performance in writing different kinds of essays and self regulation among the secondary students. The total population of this study, consisted of (51) female students of the 5th Secondary grade in Al –kawarzmi School in Erbil during the academic year 2015-2016. The chosen sample consisted of 40 female students, has been divided into two groups. Each one consists of (20) students to represent the experimental group and the control one. Brainstorming technique is used to teach the experimental group, and the conventional method is used to teach the control group. The study inst
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Financing is one of the important pillars for activating and activating the agricultural sector, through which we can see an agricultural project on the ground. However, supplying the agricultural sector with financial resources requires a credit policy that is capable of making the right financing decision, because the financial resources are limited. The credit policy, and the financing decision, must be the best use not only to provide the necessary money, but to work to provide everything that would develop and activate the agricultural sector.
The transformation of the Agricultural Cooperative Bank of Iraq from specialized banking to the overall would lead to a decrease in the volume
... Show MoreThe adopted method in the teaching of history is conservation and indoctrination in all grades, and this will lead to a lack of students interact with teachers in the course of the lesson, and poor use of teachers to questions that raise students' thinking during the lesson, which leads to a lack of interest in the topic of the lesson and wasting opportunities contribution making it the teacher at the center of the educational process, and to provide arrogating the researcher to contribute to teaching style with the belief that the use of this method of teaching could lead to overcome the difficulties and problems faced by the teaching material.
And there are educational complexes integrated approac
... Show MoreThe international financial accounting and reporting standards IFRS/IAS represent the set of rules and foundations that the economic entity must follow in the measurement, presentation, and disclosure of the elements of the financial statements, the implementation of adopting the international financial reporting standards contributes to improving the qualitative characteristics of accounting information, so the current research aims to explain the role of adopting the International Accounting Standard (IAS) in improving the qualitative characteristics as well as analyzing the impact of the adoption of IAS.1 in improving the qualitative characteristics of accounting information within the financi
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