An experimental and numerical study has been carried out to investigate the heat transfer by natural convection in a three dimensional annulus enclosure filled with porous media (silica sand) between two inclined concentric cylinders with (and without) annular fins attached to the inner cylinder under steady state condition; The experiments were carried out for a range of modified Rayleigh number (0.2 ≤Ra*≤ 11) and extended to Ra* =500 for numerical study, annulus inclination angle of (δ = 0˚, 30˚, 60˚ and 90˚). The numerical study was to write the governing equation under an assumptions used Darcy law and Boussinesq’s approximation and then solved numerically using finite difference approximation. It was found that the average Nusselt number depends on (Ra*, Hf, δ and Rr) and the maximum value of the local Nusselt number for vertical cylinder is about two times as large as that of the horizontal case. The results showed that, increasing of fin length increases the heat transfer rate for any fins pitch unless the area of the inner cylinder exceeds that of the outer one, then the heat will be stored in the porous media. A correlation for Nu in terms of Ra, Rr and δ, has been developed for inner cylinder. A comparison was made between the results of the present work and with other researches for the case without fins and excellent agreement was obtained and reveals deviation less than 5 % for average Nusselt number.
Investigating the thermal and electrical gains and efficiencies influence the designed photovoltaic thermal hybrid collector (PVT) under different weather conditions. The designed system was manufactured by attaching a fabricated cooling system made of serpentine tubes to a single PV panel and connecting it to an automatic controlling system for measuring, monitoring, and simultaneously collecting the required data. A removable glass cover had been used to study the effects of glazed and unglazed PVT panel situations. The research was conducted in February (winter) and July (summer), and March for daily solar radiation effects on efficiencies. The results indicated that electrical and thermal gains increased by the incre
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In view of the fact that high blood pressure is one of the serious human diseases that a person can get without having to feel them, which is caused by many reasons therefore it became necessary to do research in this subject and to express these many factors by specific causes through studying it using (factor analysis).
So the researcher got to the five factors that explains only 71% of the total variation in this phenomenon is the subject of the research, where ((overweight)) and ((alcohol in abundance)) and ((smoking)) and ((lack of exercise)) are the reasons that influential the most in the incidence of this disease.
The Arab realized that proverbs and their stories had a great literary and linguistic significance, accordingly, they collected them from their sources and wrote them down. Thus, researchers went in studying them in different directions. The aim of the present research is thus to study the stories of proverbs in the Holy Qur’an, Prophet’s hadiths, and in the sayings of Arabs. Such a study helps to show the extent of the relevance of their stories to the proverbs, their literary values, the points of convergence between them and what they highlight, and the extent of their proximity to reality. It further helps to determine the factors that contributed to the transformation of Quranic verses, Prophet’s hadiths, and some phrases of s
... Show MoreThe research aims to study and definition of the concept of creative accounting and motives adopted by the management of companies to achieve their own goals and their impact on the reliability of the financial statements and the tax settling accounts and whether that tax administration is able to detect and limit the creative accounting practices and impose legal sanctions deterrent against companies The research has come to a set of conclusions, including:
- The administration motives in the use of creative accounting methods, some internal motives related to the interests of the administration in maximizing profits to increase incentives and rewards, others are external, such as the impact on stock prices or reduce the am
This paper presents seven modified Adomian Decomposition Method (ADM) techniques for efficiently solving initial value problems, especially those involving non-homogeneous and nonlinear differential equations. While the classical ADM is effective for linear homogeneous cases, it has difficulties solving more complex problems. The proposed modifications—from MADM1 to MLADM—include Maclaurin and Taylor expansions, Laplace transforms, and single-step iterations.• These modifications enhance convergence, reduce complexity, and improve accuracy.• Each method offers specific advantages, such as accelerating convergence (MADM2, RADM4), simplifying computation (TSADM5), and achieving higher accuracy (MLADM).• Numerical examples confirm th
... Show MoreThis study aims to identify the amount of the effect of the ability to learn the individuals within the organization on the accumulation of intellectual capital and the role it plays in improving the performance of the organization, and to achieve that, the researcher designed a questionnaire to collect data and information from the surveyed respondents and analyzed using SPSS software, the study concluded after testing hypotheses to have a direct impact between the capacity for organizational learning and the accumulation of intellectual capital, which in turn affects the accumulation of intellectual capital as a positive and direct impact on the performance of the organization, al
... Show MoreThe research deals with the formal characteristics of folklore in contemporary Iraqi ceramics as a comparative study between the two potters Siham Al-Saudi and Sajida Al-Mashayikhi.
The research consists of four chapters. The first chapter is concerned with the research problem, the importance, the objectives, and the limits of the research, while the aim of the research answers the following question: The method and mechanisms of employing the traditional elements and vocabulary in the products of the potters “Seham Al-Saudi and Sajida Al-Mashaikhi”.
The second chapter came in the theoretical framework of the investigations and includes: The first topic: The second topic the movement in shaping contemporary Iraqi ceramics, whi