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Natural convection in an annular space provided with metal foam fins attached to the inner cylinder is studied numerically. The metal foam fins made of copper were inserted in different axial sections with three fins in each section. The temperature of the inner cylinder is kept constant while the annular outer surface is adiabatic. The thickness effect of the inner pipe wall was considered. Naiver Stokes equation with Boussinesq approximation is used for the fluid regime while Brinkman-Forchheimer Darcy model is used for metal foam. In addition, the local thermal non-equilibrium condition in the energy equation of the porous media is presumed. The effect of Rayleigh number and number of foam fins in the axial direction, on fluid flow and heat transfer characteristics, were examined. The current model was valid with the available published results and good agreement is noticed. Results showed that as the Rayleigh number increases the dominated of convection mode increases and average Nusselt increases. It was found that at Rayleigh of 106 Nusselt reached its higher value which is 4.6 for the case of adding seven axial metal foams. A comparison between adding foam fins and copper fins was established for a range of Rayleigh numbers between 104 and 106. It showed a good enhancement in Nusselt number and the greatest enhancement percentage was 45.9% at Rayleigh equal 106 for the case of using seven sections of foam fins. |
The Paleocene benthic foraminiferal zonation of the Umm Er Rhadhuma Formation from the borehole (K.H 12/7), South Anah City (Western Iraq), has been re-studied and re-analyzed precisely based on the large benthic foraminifera (LBF). They are represented by two biozone Rotorbinella hensoni Partial Range Zone, recorded from the Lower and middle parts of the Umm Er Rhadhuma Formation and Lockhartia praehaimei Partial Range Zone determined Uppermost of this unit, and dated to be the Selandian – Thanetian stage. Almost all the biogenic (micro and macro) and non-biogenic constituents, including large benthic foraminifera, Algae, Echinoderm, Bryozoans, Oyster, Gastropod fragments, and peloids, in addition to lithofacies types, indicate t
... Show MoreABSTRACT Backgrounds: Maxillary canine impaction is complicated and time consuming to treat, for being highly diverse in inclination and location; it may be a companied by root resorption of the neighboring teeth. CBCT has been used for its' diagnostic reliability in localization of impacted canine and revealing its' serious local complications. Objectives: Localization of maxillary impacted canine using cone beam computed tomography for assessment of angulation, distance from occlusal plane, alveolar width and proximity to adjacent teeth. Subjects and Methods: The study sample was 33 subjects 16 females and 17 males attended to Al-Wasitti general hospital in Baghdad city-Oral and maxillofacial radiology department for CBCT scan investigati
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Arzı Kanber/Kamber hikayesi Anadolu, Rumeli, Azerbaycan, Türkmenistan ve Irak gibi Türk dünyasının birçok yerinde birden fazla varyantı bulunan, çok sevilen ve yaygın olarak anlatılan aşk ve dramatik maceralı bir halk hikayesidir. Türk halk hikayelerinin en popüler olanlarından biri sayılan Arzı Kanber/Kamber hikayesi, Anadolu'nun birçok yöresinde bilinmesine rağmen Irak Türkmenleri arasında daha çok sevildiği ve yaygın olarak anlatıldığı tespit edilen birden fazla varyantından da görülebilir. Irak Türkmenleri arasında günümüze kadar hikayenin iki varyantı tespit edilmi
... Show MoreThis paper investigates the performance evaluation of two state feedback controllers, Pole Placement (PP) and Linear Quadratic Regulator (LQR). The two controllers are designed for a Mass-Spring-Damper (MSD) system found in numerous applications to stabilize the MSD system performance and minimize the position tracking error of the system output. The state space model of the MSD system is first developed. Then, two meta-heuristic optimizations, Simulated Annealing (SA) optimization and Ant Colony (AC) optimization are utilized to optimize feedback gains matrix K of the PP and the weighting matrices Q and R of the LQR to make the MSD system reach stabilization and reduce the oscillation of the response. The Matlab softwar
... Show MoreIn this work, the preparation of new multidentate Schiff-base lig and and its metal complexes are described. The formation of the lig and{ 2,2`((5-methyl-1,3-phenylene)-bis-(oxy))-bis-N`(E`)-2- hydroxybenzylideneacetohydrazide}[H2L] was prepared from the reaction {2,2-((5-methyl-1,3-phenylene)-bis-(oxy))- di-(acetohydrazide)}[M]precursor and salicylaldehyde in a 1:2 mole ratio, respectively. The reaction of the lig and [H2L] with (Cr+3 , Mn+2 and Fe+2 )metal ions in a 1:2 (L:M) mole ratio. Ligand and complexes were characterised via spectroscopic analyses; [FT-IR, UV-Vis spectroscopy,(C.H.N) microanalysis, chloride content, thermal analysis(TG), electrospray mass, magnetic susceptibility and conductivity measurements. The characterisation d
... Show MoreThis study investigates the impact of spatial resolution enhancement on supervised classification accuracy using Landsat 9 satellite imagery, achieved through pan-sharpening techniques leveraging Sentinel-2 data. Various methods were employed to synthesize a panchromatic (PAN) band from Sentinel-2 data, including dimension reduction algorithms and weighted averages based on correlation coefficients and standard deviation. Three pan-sharpening algorithms (Gram-Schmidt, Principal Components Analysis, Nearest Neighbour Diffusion) were employed, and their efficacy was assessed using seven fidelity criteria. Classification tasks were performed utilizing Support Vector Machine and Maximum Likelihood algorithms. Results reveal that specifi
... Show MoreErratum for Organic acid concentration thresholds for ageing of carbonate minerals: Implications for CO2 trapping/storage.