An experimental and numerical study has been carried out to investigate the heat transfer by natural convection and radiation in a two dimensional annulus enclosure filled with porous media (glass beads) between two horizontal concentric cylinders. The outer cylinders are of (100, 82 and70mm) outside diameters and the inner cylinder of 27 mm outside diameter with (or without) annular fins attached to it. Under steady state condition; the inner cylinder surface is maintained at a high temperature by applying a uniform heat flux and the outer cylinder surface at a low temperature inside a freezer. The experiments were carried out for an annulus filled with
glass beads at a range of modified Rayleigh number (4.9 ≤ Ra≤ 69), radiation parameter (0<Rd<10), with fin length of (Hf=3, 7 and 11mm), with radius ratios of (Rr=(r1/r2) =0.1405,0.2045, 0.293 and 0.3649 ), number of fins (n=0, 12, 23 and 45). Finite difference method with Boussinesq's approximation is used to solve the continuity, energy and momentum equations.
The numerical solution is capable of calculating the streamline, the temperature field, the velocity field, the local and average Nusselt number. A computer program in Mat lab has been built to carry out the numerical solution. The numerical study was done for a range of modified Rayleigh number (4.9 ≤ Ra ≤ 300). Results show that the average Nusselt number is nearly constant for Ra less than 100 and increased with an increase in modified Rayleigh number.
Nusselt number hardly affected by glass beads size and insignificant affected by Rd for Ra less than 100. Decreasing Rr cause clearly increase in average Nusselt number and increasing fin length or fin number decrease heat transfer.
We refer in this research into linguistic binaries, try rounding of simiaei news analysis. It is known that there are branches of Linguistics called social Linguistics, divided into communicative Linguistics and media. Perhaps the best justification for the inclusion of a new curriculum in media studies is a semiotic analysis of the news. I›ve turned the speech, language and communication studies in relation to different disciplines, many research projects, and returned only old curriculum, speed shift in thought, proportional to the revolution in information and communication technology, for reality imposed on the entire world, researchers are the first affected by this enormous humanitarian Almanza. Alsimiaaeon still shy away from an
... Show MoreIn addition to being a religious book with high human and moral themes, Nahj al-Balagha is considered a mirror of Arab culture and a literary masterpiece at the height of eloquence and eloquence, and because proverbs in the form of short, concrete and understandable phrases for everyone, experiences, thoughts and convey ideas, Imam Ali (AS) used it to facilitate the understanding of various political, social and moral concepts. In this article, we intend to criticize the way Dashti, Shahidi and Foladvand translated it by using Newmark's model due to the importance and cultural reflections of proverbs in understanding the cultural atmosphere governing Nahj al-Balagheh. In his evaluation model, Newmark divides cult
... Show MoreThis research includes the principles of the democracy، and to which extent it can contribute in establishing these principles. Democracy is not only to hold parliamentary or presidential elections but also the result of these elections wills it lead to the emergence of an integrated regime that can actually expresses the citizen's rights and to which extent those citizens can contribute in that regime and control it. Since 2005، when the first elections took place in Iraq after the US occupation of Iraq 2003، Iraqi people are looking to a rule that represented them and achieve their interests after getting rid of the totalitarian regimes and establishing an institutional regime that work by democratic means in order to achieve the so
... Show MoreAbstract
In this investigation, Al2O3 nano material of 50nm particles size were added to the 6061 Al aluminium alloy by using the stir casting technique to fabricate the nanocomposite of 10wt% Al2O3. The experimental results observed that the addition of 10wt% Al2O3 improved the fatigue life and strength of constant and cumulative fatigue. Comparison between the S-N curves behaviour of metal matrix (AA6061) and the nanocomposite 10wt% Al2O3 has been made. The comparison revealed that 12.8% enhancement in fatigue strength at 107cycles due to 10wt% nano reinforcement. Also cumulative fatigue l
... Show MoreThe study aimed to investigate the role of Dectin-1 and Card-9 in pathogenicity of inflammatory bowel disease (IBD). This investigations involved 150 blood samples for IBD patients which divided in to two groups (50 for crohns disease CD (G2) and 50 for ulcerative colitis UC (G3)). All a apparently (male and female) attended to) Al-Kindy hospital) in Baghdad city, department of Gastroenterology. and all of thin were diagnosis by consulters medical staff and pathologists with age range 15-65years average 40 years. in addition to 50 blood samples were collected from apparently healthy individuals as control group (G1). 10 ml were withdrawn from all participants, 5ml for the immunological study which carried by ELISA technique and 5 ml used fo
... Show MoreThe aim of this study to investigate the tongue morphology and histology in house gecko Hemidactylus flaviviridis using light and scanning electron –microscopy (SEM ) technique.The morphology result revealed the presence of three parts : apex , body and lingual root .The light microscopy result showed that the tongue is covered with mucous membrane composed of non keratinized stratified squamous epithelium based on lamina propria which contain bundles of striated muscles its fibers in different directions including connective tissue , blood vessels and nerves. The lingual mucosa of the dorsal surface is covered with different pattern of lingual papillae which are widely distributed all over the dorsal surface except the apex. Noticed on t
... Show MoreThe present study combines UV-Vis spectrophotometry and dispersive liquid-liquid microextraction (DLLME) for the preconcentration and determination of trace level clidinium bromide (Clid) in pharmaceutical preparation and real samples. The method is based on ion-pair formation between Clid and bromocresol green in aqueous solution using citrate buffer (pH = 3). The colored product was first extracted using a mixture of 800 µL acetonitrile and 300 µL chloroform solvents. Then, a spectrophotometric measurement of sediment phase was performed at λ = 420 nm. The important parameters affecting the efficiency of DLLME were optimized. Under the optimum conditions, the calibration graphs of standard -1 (Std.), drug, urine and serum were ranged
... Show More