This article deals with the impact of including transverse ribs within the absorber tube of the concentrated linear Fresnel collector (CLFRC) system with a secondary compound parabolic collector (CPC) on thermal and flow performance coefficients. The enhancement rates of heat transfer due to varying governing parameters were compared and analyzed parametrically at Reynolds numbers in the range 5,000–13,000, employing water as the heat transfer fluid. Simulations were performed to solve the governing equations using the finite volume method (FVM) under various boundary conditions. For all Reynolds numbers, the average Nusselt number in the circular tube in the CLFRC system with ribs was found to be larger than that of the plain absorber tube. Also, the inclusion of transverse ribs inside the absorber tube increases the average Nusselt number by approximately 115% at Re = 5,000 and 175% at Re = 13,000. For all Reynolds numbers, the skin friction coefficient of the circular tube with ribs in the CLFRC system is larger than that of the plain absorber tube. The coefficient of surface friction reduces as the Reynolds number increases. The performance assessment criterion was found to vary between 1.8 and 1.9 as the Reynolds number increases.
Gallium arsenide diamondoids structural and vibrational properties are investigated using density functional theory at the PBE/6-31(d) level and basis including polarization functions. Variation of energy gap as these diamondoids increase in size is seen to follow confinement theory for diamondoids having nearly equiaxed dimensions. Density of energy states transforms from nearly single levels to band structure as we reach larger diamondoids. Bonds of surface hydrogen with As atoms are relatively localized and shorter than that bonded to Ga atoms. Ga-As bonds have a distribution range of values due to surface reconstruction and effect of bonding to hydrogen atoms. Experimental bulk Ga-As bond length (2.45 Å) is within this distribu
... Show MoreBasically, media studies focused on the important role of the blogs in boosting the democratic process in the Arab States. Blogs also worked on creating an alternative media for the public that maintained freedom of expression. However, media studies ignored the status of the blogs in the social and cultural fields.
The current study tries to tackle the socio-cultural dimensions of the blogs by means of showing how the blogs construct the self. The researcher is going to conduct interviews with the bloggers. He will also carry out a semiotic analysis that may reveal the strategies used by the bloggers. Besides, he tries to identify the realistic and traditional frames in which the social relationships are buil
A novel ligand, (E)-5-((2-hydroxy-4,6-dimethylphenyl)diazenyl)-2,3-dihydrophthalazine-1,4- dione, was synthesized through the reaction of 3,5-dimethylphenol with the diazonium salt of 5-amino-2,3-dihydrophthalazine-1,4-dione. The ligand underwent characterization through the utilization of diverse spectroscopic methods, including UV-Vis, FT-IR, 13C, and 1H-NMR, alongside Mass spectroscopy and micro elemental analysis (Carbon, Hydrogen, Nitrogen, and Oxygen). Metal chelates of transition metals were prepared and analyzed using elemental analysis, mass spectra, atomic absorption, UV-Vis, FT-IR spectral analysis, as well as conductivity and magnetic measurements. The investigation into the compounds’ nature was conducted by utilizing mole r
... Show MoreIn order to achieve optimal plant growth and production, essential nutrients must be readily available in adequate quantities and in a balanced proportion to give a good yield, especially broccoli which has health benefits that may not be found in many other plants. For this purpose, this experiment was carried out during the seasons 2019/2020 in the botanical garden of the Department of Biology, College of Science for Women, University of Baghdad, to study the effects of nitrogen and sulphur and their interaction on eight parameters reflecting the overall traits of vegetative growth, yield, and chlorophyll content of broccoli Brassica oleracea L. (var. italic JASSMINE F1 Hybrid). A factorial design with three replicates was use
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The researcher in theological sects finds that the controversial issues between the owners of the sects are many, filled with the books of the sects, articles and creeds, and when examining these books it became clear to us that the dispute is related, some of it is related to the meaning and some of it is related to the words and it is many, explained to us by rhetorical terminology such as guidance and delegation, Interpretation and others, and part of it is what is called the verbal disagreement, and sometimes it is by using common possible expressions of truth and falsehood, as in the saying of the Kharijites, “The judgment is only for God,” and some of it is related to something outside th
It has become familiar to see alchemy as a methodological approach that combines conscious, diverse, psychological, social, structural, and discrete approaches in the communications technology that Marshall McLuhan found to be able to extend our bodies and senses, The media discourse has a deep and superficial structure produced by the first, with its social, cultural and historical backgrounds, in a context that connects the image with the word, as the "meanings are made" - everywhere, as described by Jonathan ) In fashion, in the arts as a whole, and from its "signs" Our analysis of «meaning», in the media, and communication through advertising, magazines, newspapers, television, and the Internet. Therefore, alchemy is preoccupied wi
... Show MoreThe current research aims to identify the problems and needs for both college of political science and college of engineering’s students. The sample was (100) male and female student. The results showed bunch of problems which could be organized descendingly, the scientific domain ranged between (2 - 2.42), the mean of the psychological domain was (2.85), the moral domain ranged between (2.2 – 2.28)m the problems of study earned (2.30), the material domain got (1.95), the medical and social domain obtained (1.925), and finally, the family domain received (1.887).
The development taking place in various sports in performance, which was and still takes a large part by focusing on the specialized level of the players, whether in training or competition in all sports, including handball. In the competition (the match) by measuring the hormone beta-endorphin as well as. To identify the changes that occur in some biochemical variables as a result of the high effort in the competition (the match) by measuring lactic acid and the hormone aldosterone). The researcher used the descriptive method, the pre and post test of one group Due to the nature of the research, the research community was represented by Al-Shorta Sports players and Al-Jaish club players in handball, as they numbered (24) players from the t
... Show MoreTill now, isatin derivatives have received a lot of interest in organic and medicinal chemistry due to their significant biological and pharmacological activities. Schiff’s and Mannich bases of isatins are an effective group of heterocyclic derivatives that play a significant role in medicinal chemistry as antimicrobial agents. In light of these facts, new Schiff bases and Mannich bases of isatin were synthesized. The monomer Mannich bases; 3(a-e) have been synthesized by reacting isatin with different secondary amines, piperidine, morpholine, and pyrrolidine, dimethylamine, diphenylamine, separately, and formaldehyde, while the dimer (5) formed by using piperazine and formaldehyde which then react separately with Phenylhydrazine
... Show MoreThis study came to show the importance of long hope and its extent on human life, and I found that through the research, the majority of the scholars did not address this topic separately, and did not explain the travails of this situation and the worldly problems it causes to its owner, and the consequences that fall upon it in the hereafter. Most of the studies inside of the books consisted of a simple presentation of this problem and an explanation of the remedies that came to us from the Qur'an and the hadiths and the Sunnah, and on the sayings of the imams of guidance (may the best prayers and peace be upon them), and on the chosen companions and followers, may God be pleased with them, but the length of hope does not stop At a certain
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