Preferred Language
Articles
/
WBj_aZQBVTCNdQwCgRVc
The Convective Instability of BEK Family of Non-Newtonian Rotating Boundary-Layer Flows
...Show More Authors

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.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Jan 31 2019
Journal Name
Journal Of The College Of Education For Women
Geographical distribution efficiency of the civil defense centers in the city of Baghdad
...Show More Authors

The city suffers from the weakness of the civil defense to provide services where there are clusters of residential Guy covered services for that requires the study of the geographic distribution of the civil defense centers in Baghdad care great because they take care of Protect the population and their own property and protect state institutions. Through a review of the problems faced it is expected that this study will help decision-makers to take appropriate steps to develop this service core

View Publication Preview PDF
Publication Date
Tue Mar 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
Study of the marketing supply chain of the fuel oil productUsing transport models
...Show More Authors

The marketing logistic chain, as an integrated system aimed to balance the achievement of its main opposite objectives which represented in the access to the best service presented to the customer with lowest possible logistic costs especially the transportation costs, where encourages the researcher to choose the second objective as a field of this study in order to reduce the transportation costs in the final link of marketing logistic chain which related to delivering of fuel oil to the customer that falls within organizational responsibilities of the company under consideration (Oil Marketing Company) and also known in a brief name by (SOMO) through two methods, the first is by functioning quantative techniques by using trans

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
The Effect of Chlorine Concentration on the Optical Constants of SnS Thin Films
...Show More Authors

Chlorine doped SnS have been prepared utilizing chemical spray pyrolysis. The effects of chlorine concentration on the optical constants were studied. It was seen that the transmittance decreased with doping, while reflectance, refractive index, extinction coefficient, real and imaginary parts of dielectric constant were increased as the doping percentage increased. The results show also that the skin depth decrease as the chlorine percentage increased which could be assure that it is transmittance related.

View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Fri Apr 05 2024
Journal Name
Techhub Journal
The effect of suggested exercises on improving the kinesthetic response of soccer goalkeepers
...Show More Authors

View Publication Preview PDF
Publication Date
Fri Jun 30 2023
Journal Name
College Of Islamic Sciences
The artistic image of flowers in the poetry of Abi Waki` al-Tanisi
...Show More Authors

 

Man was closely associated with nature in its various forms, as it represented the incubator for him in all areas of his life, so writers often made it a material for their literature and a fertile ground for their productions, so it appeared in its various forms and man’s need for it, its good and its bad in literature throughout history, and the Arabs are like Other nations, since the pre-Islamic era, nature was an important outlet and a refuge for poets in the production and creativity of literature and to this day, and when we talk about a poet from the Fatimid state, we find that nature - especially spring and its flowers - in that period took its take from literature and represented a phenomenon for many Among the

... Show More
View Publication Preview PDF
Publication Date
Mon Feb 14 2022
Journal Name
Journal Of Educational And Psychological Researches
The Relationship of Noise Pollution to the Mental Health of Among University Students
...Show More Authors

The present study deals with the relationship of noise pollution to the mental health of university students, through the researcher field study with the use of descriptive Correlative approach to investigate this relationship. Noise is one of the elements of environmental pollution that people often expose to in their environment. The problem of noise has been exacerbated now because of cultural and technological progress in crowded cities. As a result, the researchers studied noise as an environmental stimulus that affects the mental health of the human being.The researchers, through their current research try to study a very serious problem, which is the problem of noise pollution on the health side of university students as a

... Show More
View Publication Preview PDF
Publication Date
Sat Jan 05 2019
Journal Name
Iraqi Journal Of Physics
Study the effect of sodium hydroxide solution on the thermal conductivity of nanocomposites
...Show More Authors

In this research, hand lay- up technique is used to prepare samples from epoxy resin reinforced with multi- walled carbon nanotubes in different weight fractions (0, 2, 3, 4, 5) wt%. The immersion effect by sodium hydroxide solution (NaOH) at normality (0.3N) for a period of (15 days) on the thermal conductivity of nanocomposites was studied, and compared to natural condition (before immersion). The thermal conductivity of epoxy nanocomposites specimens were carried out using Lee’s disk method. The experimental results showed that thermal conductivity increased with increase weight fraction before and after immersion for all specimens, while the immersion effect leads to decrease thermal conductive values compared to thermal conductivi

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Sep 30 2014
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Study the Feasibility of Alumina for the Adsorption of Metal Ions from Water
...Show More Authors

The present work describes the adsorption of Ba2+ and Mg2+ions from aqueous solutions by activated alumina in single and binary system using batch adsorption. The effect of different parameters such as amount of alumina, concentration of metal ions, pH of solution, contact time and agitation speed on the adsorption process was studied. The optimum adsorbent dosage was found to be 0.5 g and 1.5 g for removal of Ba2+ and Mg2+, respectively. The optimum pH, contact time and agitation speed, were found to be pH 6, 2h and 300 rpm, respectively, for removal of both metal ions. The equilibrium data were analyzed by Langmuir and Freundlich isotherm models and the data fitted well to both isotherm modes as indicated by higher correlation of deter

... Show More
View Publication Preview PDF
Publication Date
Sun Nov 18 2018
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Comparison Between Standard Bayes Estimators of the Reliability Function of Exponential Distribution
...Show More Authors

   In this paper, a Monte Carlo Simulation technique is used to compare the performance of the standard Bayes estimators of the reliability function of the one parameter exponential distribution .Three types of loss functions are adopted, namely, squared error  loss function (SELF) ,Precautionary error loss function (PELF) andlinear exponential error  loss function(LINEX) with informative and non- informative prior .The criterion integrated mean square error (IMSE) is employed to assess the performance of such estimators

View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Thu Feb 24 2022
Journal Name
Journal Of Educational And Psychological Researches
The Psychometric Properties of the Arabic Version of Nomophobia Scale among Omani Youth
...Show More Authors

The current research aimed to investigate the psychometric characteristics of the Arabic version of the Nomophobia scale for the Omani youth. The scale was administered to a random sample of students from public and private universities and colleges in Oman. The research sample consisted of 2507 students, of whom 868 males and 1639 females. The validity of the measure was first checked by presenting the scale to a group of experts in this field. Then the exploratory and confirmatory factor analysis was carried out. The exploratory factor analysis revealed the existence of three main factors: the fear of connectivity loss, the fear of communication loss with others, and the fear of network outages. These factors accounted for 65.6% of the

... Show More
View Publication Preview PDF