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 study aims to demonstrate the role of strategic renewal in enhancing organizational immunity through strategic renewal mechanisms represented by (Reanimating, Rejuvenation, Venturing, and restructuring). The main idea of this study relates to the extent to which organizations’ immunity is achieved through strategic Renewal mechanisms, by measuring these dimensions with Organizational immunity represented by organizational learning, organizational memory, and organizational DNA. The study population was the headquarters of the Iraqi Ministry of Education, and the sample included (330) individuals from the upper, middle, and lower leadership levels. Several statistical methods were used to deal with the results of the questionna
... Show MoreThe aim of this research is to find out the satisfaction functional for faculty members
To Girls College of education at the University of Baghdad, and to find out the differences in this variable according to gender and qualification of education.
The sample was chosen from 60 teachers (males – females), they applied a questionnaire consisting of (30) paragraphs after the verifying of sincerity and persistence for paragraphs.
The main findings of the studies,
The results are indicated that the samples (faculty members) have a good level of satisfaction functional. In addition, results are shown; there are no significant differences of statistically between males and females for the faculty members. However, results are sho
Objective: This research was carried out in rats in a special place of the laboratory of histopathological diseases in the period 6/9/2018 until 23/11/2018, this study to detect effect of the addition of the alcohol extract of ginger in the reduction of fat in liver tissue of rats. Method: Eight groups and replicates for each group. The groups were homogenous in weights and were placed in 13 cages. Each group consisted of 10 rat and at 5 fares each. In the first treatment, rat were fed on regular feeding without adding and feeding rats in the second treatment sessions add to it the alcoholic extract of ginger in Turkey 150 mg/kg. The third group is the same as the normal food after adding the alcohol extract of ginger at a concentration of
... Show MoreThe purpose of this study is to assess the level of computer literacy of the students at AlQuds open university in Tulkarm Branch. The study investigates the effects of the variables of gender, specialization, academic level, owning a personal computer, internet communication, and own an email account on the level of computer literacy. A test of computer literacy was constructed by the researchers consisting of (37) multiple choice items with a reliability rate (0.85). The study population consisted of (4100) students, while the sample contained (352) students. The study revealed that the level of computer literacy of the students at AlQuds Open University in Tulkarm Branch was (66.2 %) which is educationally acceptable. It also
... Show MoreFear, harvesting, hunting cooperation, and antipredator behavior are all important subjects in ecology. As a result, a modified Leslie-Gower prey-predator model containing these biological aspects is mathematically constructed, when the predation processes are described using the Beddington-DeAngelis type of functional response. The solution's positivity and boundedness are studied. The qualitative characteristics of the model are explored, including stability, persistence, and bifurcation analysis. To verify the gained theoretical findings and comprehend the consequences of modifying the system's parameters on their dynamical behavior, a detailed numerical investigation is carried out using MATLAB and Mathematica. It is discovered that the
... Show MoreThe current research aims to verify the impact of digital leadership as an independent variable, in the effectiveness of crisis management as a response variable through centralizing strategic vigilance in the faculties of the University of Baghdad and its departments, and to investigate the level of interest of its leaders and subordinates in research variables, as well as coming up with recommendations that contribute to strengthening the practices of the three variables. In the university under study, and based on the researcher’s interest to diagnose the influence relationship between the variables, because of their importance in the university’s headquarters and its members on the one hand, and its refl
... Show MoreCrude oil still affects many countries because it is one of the essential fuel sources. It makes life more manageable in modern communities and cannot be overstated because it is easy to use and find. However, the pollution caused by its use in industries such as mining, transportation, and the oil and gas business, especially soil pollution, cannot be ignored. Soil pollution is an issue in most communities because it influences people and ecology. Accidental infusions and spills of ore oils are prevalent occurrences leading to the entire or fractional exchange of the soil pore fluid by oil-contaminated soils that have affected the geotechnical engineering properties. The liquid limitations for polluted soil grades silty loam and sa
... Show MoreThe research aims to verify the Role of Internal Auditing in Assessing the Risks of Strategic Operations (Acquisition) and then reflect on management decisions. Since all corporations wish to expand, growth and domination of the market may expose them to multiple risks that lead to failure. The research assumes two main hypotheses. First, there is no role for internal audit in evaluating the strategic operations (acquisition). Second, there is no relationship between internal auditing in assessing the risks of strategic operations (Acquisition) and management decisions. The data was collected by using a questionnaire distributed to a group of private bank employees. The statistical analysis regarding research rejected the two hyp
... Show MoreAbstract
The research aims to examine the effect of Hawkins' strategy on students in the fourth grade of primary school in the General Directorate of Education in Baghdad / Karkh 3 for the academic year (2020-2021). The research was limited to the topics of the Arabic language grammar book for the fourth grade of primary school. The researcher developed the research hypothesis, which is: that there is no statistically significant difference at the significance level (0.05) between the average scores of the experimental group students who study using the Hawkins strategy and the average scores of the control group students who study in the traditional method in the achievement test. The researcher set a number of
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