This study reports on natural convection heat transfer in a square enclosure of length (L=20 cm) with a saturated porous medium (solid glass beads) having same fluid (air) at lower horizontal layer and free air fill in the rest of the cavity's space. The experimental work has been performed under the effects of heating from bottom by constant heat flux q=150,300,450,600 W/m2 for four porous layers thickness Hp (2.5,5,7.5,1) cm and three heaters length δ(20,14,7) cm. The top enclosure wall was good insulated and the two side walls were symmetrically cooled at constant temperature. Four layers of porous media with small porosity, Rayleigh number range (60.354 - 241.41) and (Da) 3.025x10-8 has been investigated. The obtained data of temperature from testing rig are used to extract the temperature distribution, local Nusselt number and average Nusselt number. Moreover, a comparison between the numerical result of the same problem published recently and present experimental results has been executed and discussed. It is evinced that; the heat transfer and fluid flow are affected by thickness of porous layer and be maximum at porous layer thickness (0.25L) with larger heater length(20cm) and heat flux (q= 600 Watt/m2) which is approximately (180%) for the average Nu when compared with (Hp=0.75L). Also, the effect of the increasing in heater length (δ) on the averaged heat transfer enhancement is more pronounced for large heater size and 25% of average enhancement is achieved for (δ=20cm) compared to (δ=7cm). However, the greater temperature distribution is found at Hp=2.5cm and 5cm at bottom and first quarter of the cavity (heater surface height Y=0 cm and Y=5 cm) respectively and minimum temperature at top (insulation wall Y=20 cm). Nearly, same shape for heat transfer for different case with clearly difference at small heater (δ=7cm).
The organizations and institutions of the developed countries have given attention to the subject of the knowledge economy by using advanced technology in the function of tax examination because of the important and effective role in ensuring the accuracy of the tax accounting process procedures, But the General Commission of taxes is still using traditional methods in the field of tax examination which affects the performance of its work. This research aims to explain the level of effect on introducing advanced methods of Economics and knowledge represented by advanced communication technology in the field of practicing tax examination function in the General Commission of taxes, A questionnaire has been used as a mea
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The importance of any educational or scientific research through its intellectual arena of facts supply the individual and society, Supports Knowledge and Science Group, which raised will be locked in these topics in the future.
This research seeks to shed light on the image and the role of women and men in the books of the Arabic language in primary education (primary), To illustrate the negative effects of the phenomenon of sexism in textbooks, And its negative impact on emerging, And stay away as much as possible about the distinction between the sexes in the roles and qualities in textbooks traditional stereotypes and remove that put both sexes templates hinder the development of the individual and t
One of the most important phenomena facing the athlete is the anxiety of sports competition, as he faces many psychological problems during training and in competitions of psychological tension, fear and anxiety that accompany him sometimes, which leads to affecting his level, and sports competition anxiety is a special type of anxiety that occurs in the athlete It is related to the attitudes of sports competitions and that participation in sports competitions and the associated emotional experiences are among the important factors that motivate the practice of sports activity and try to advance and develop his sports level. It is assumed that when the individual begins to practice any activity, he aims to reach a level or degree of achie
... Show MoreThere are many harmful acts that occur from drunkards in this case, especially those resulting from car accidents. The world is witnessing dozens or even hundreds of car accidents due to alcohol consumption. These accidents often result in serious injuries that could lead to the death of the drunk driver and those in the car As well as other persons present in the other vehicles with which the incident occurred or pedestrians on the street, as well as damage to private or public property, and if the order of return of the affected persons on the pretext of civil liability (tort) is made as a direct cause of the harmful act, Is entitled Do they like this refer to the liquor seller or their provider as the culprit? Or are they not related to
... Show MoreThis research aims to study the optical characteristics of semiconductor quantum dots (QDs) composed of CdTe and CdTe/CdSe core-shell structures. It utilizes the refluxed method to synthesize these nanoscale particles and aims to comprehend the growth process by monitoring their optical properties over varied periods of time and pH 12. Specifically, the optical evolution of these QDs is evaluated using photoluminescence (PL) and ultraviolet (UV) spectroscopy. For CdTe QDs, a consistent absorbance and peak intensity increase were observed across the spectrum over time. Conversely, CdTe/CdSe QDs displayed distinctive absorbance and peak intensity variations. These disparities might stem from irregularities in forming selenium (Se) layers a
... Show MoreThis study aimed at some of the criteria used to determine the form of the river basins, and exposed the need to modify some of its limitations. In which, the generalization of the elongation and roundness ratio coefficient criterion was modified, which was set in a range between (0-1). This range goes beyond determining the form of the basin, which gives it an elongated or rounded feature, and the ratio has been modified by making it more detailed and accurate in giving the basin a specific form, not only a general characteristic. So, we reached a standard for each of the basins' forms regarding the results of the elongation and circularity ratios. Thus, circular is (1-0.8), and square is (between 0.8-0.6), the blade or oval form is (0.6-0
... Show MoreScience occupies great importance in Islamic thought. Science and learning are considered an essential part of Islamic teachings, and this importance appears in several aspects,Among them is thatScience as a means of understanding religion :Science is a means of understanding the teachings of the Islamic religion. Islam encourages thinking and rational research to understand the Holy Quran and the Sunnah of the Prophet, enabling Muslims to direct their lives and actions in accordance with the directives of their religion,And also to encourageResearch :Islam encourages scientific research and the use of reason in understanding the nature of the universe and God’s signs in it. Muslims are encouraged to study the natural and social s
... Show MoreThe research aims to determine the role of knowledge management to measure performance on a sample of faculties of Administration and Economics the University of Kufa, and to achieve this goal through a researcher from the theoretical literature and research and studies related to the construction of the scheme shows the hypothetical relationship between the variables, which was adopted by the independent variable knowledge management, distributed four variables are: (knowledge generation, knowledge storage, knowledge dissemination, the application of knowledge), as well as four variables representing the variables adopted for the performance of the university are:
(to reduce costs and increase profits, improve quality, scie
The importance of the study stems from the fact that it deals with a very important subject, namely, the pivotal role played by E-banking in achieving the competitive advantage of the banking institutions operating in Algeria. By adopting the banking institution and adopting the elements of the electronic marketing mix and developing it as required by the environment The banking system of developments will inevitably be able to achieve excellence from its competitors as each of these elements have an important role in achieving competitive advantage, we relied in this study on studies and research that directly affect the problem of the study and we have put Estep In order to activate the contribution of e-banking in achieving competitiv
... Show MoreBackground: Langerhans' cell histiocytosis (LCH) is a group of conditions affecting the reticuloendothelial system. It includes Letterer-Siwe disease, Hand-Schuller-Christian disease and eosinophilic granuloma and most often presents in childhood. Materials and methods: Twenty-five cases of LCH were diagnosed histologically and confirmed by CD1a antibody and assessed immunohistochemically using anti-RANKL and anti-RANK antibodies to evaluate osteoclastogenic mechanism. Results: Regarding jaw cases, there was a significant correlation between CD1a and RANK (P=0.016). While in the skull, highly significant correlation existed between RANK and RANKL (p=0.001). Among the sites, there was no statistically significant difference found for each
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