A numerical study of the two-dimensional steady free convection flow in an inclined annulus between two concentric square cavities filled with a porous medium is presented in this paper for the case when the side outer walls are kept with differentially heated temperature while the horizontal outer walls and the inner walls are insulated. The heated wall is assumed to have spatial sinusoidal temperature variation about a constant mean value. The Darcy model is used and the fluid is assumed to be a standard Boussinesq fluid. For the Cartesian coordinate system, the governing equations which were used in stream function form are discretized by using the finite difference method with successive under – relaxation method (SUR) and are solved by Gauss-Siedel iterative method. The upwind scheme was used for the transport terms in the energy conservation equation. The results are presented to demonstrate the streamlines, the isotherms, and the Nusselt number depending on the Rayleigh number ranging from (Ra =10 to 1000), dimension ratio from (Dr = 0.15 to 0.45), and the inclination angle from (= 0o to 45o). Also the effects of the amplitude (=0 to 1) and the wave number (f =0 to 5) of the heated side wall temperature variation on the free convection are investigated. The results show the effect of previous parameters (Ra, Dr,, , and f) on the flow fields and temperature profiles. It also show that the average Nusselt number is a strong function of the Rayleigh number, inclination angle, dimension ratio, and temperature variation. The peak value of the average Nusselt number based on the hot wall temperature is observed to occur at dimension ratio of (0.15), inclination angle of (40.1°), amplitude and wave number (1 & 0.75) for Rayleigh number of (1000).
ﺔﻴﻋﺍﺫﻹﺍ ﺕﺎﻴﻨﻘﺘﻟﺍ ﻡﺍﺪﺨﺘﺳﺍ ﰲ ﲑﺒﻛ ﺭﻮﻄﺗ ﻦﻣ ﻝﺎﺼﺗﻻﺍ ﺮﺼﻋ ﻩﺪﻬﺷ ﻱﺬﻟﺍ ﺖﻗﻮﻟﺍ ﰲ ﺔﻴﻧﻮﻳﺰﻔﻠﺘﻟﺍﻭ ﺍ ﺢﺴﻓ ﰲ ﻢﻬﺳﺃ ﺕﺎﻄﶈﺍ ﺀﺍﻮﺳ ﺔﻴﻧﻮﻳﺰﻔﻠﺘﻟﺍ ﺕﺍﻮﻨﻘﻟﺍ ﺚﺒﻟ ﻊﺳﺍﻮﻟﺍ ﻝﺎ ( ﺔﻴﺿﺭﻷﺍ ﺔﻴﻠﺑﺎﻜﻟﺍ ﻭﺃ ﺔﻴﺋﺎﻀﻔﻟﺍ ﻭﺃ ( ﱵﻟﺍ ﺔﺻﺎﳋﺍ ﺔﻴﺋﺎﻀﻔﻟﺍ ﺕﺍﻮﻨﻘﻟﺍ ﻦﻣ ﺪﻳﺪﻌﻟﺍ ﺭﻮﻬﻇ ﰲ ﺎﻀﻳﺃ ﺪﻋﺎﺳ ﺎﳑﻭ ، ﺕﺎﻴﺋﺎﻀﻔﻟﺍ ﺭﻮﻬﻇ ﻚﻟﺫ ﻞﺒﻗ ﺩﺎﺳ ﻥﺃ ﺪﻌﺑ ﺔﻴﻣﻮﻜﺣ ﲑﻏ ﺕﺎﻴﻌﲨ ﻭ
... Show MoreThe present study aims to investigate the seroprevalence rate of Toxoplasma gondii infection and its relation to some demographic factors among males in Duhok province/Iraq. A total of 424 random blood samples were collected from the male population of different ages (18-60) years and different social-economic classes. Out of 424 samples examined, 108 (25.47%) were seropositive to the anti- T. gondii antibodies; 88 (20.75%) were found seropositive for IgG, while 20 (4.72%) samples were seropositive for IgM. Regarding occupation, the highest percentage for chronic toxoplasmosis was reported in workers followed by policemen and pensioners at rates of 23.96%, 23.6%, and 23.07%, respectively. The age group 18-30 y
... Show More
(10)
(5)
BACKGROUND: The humeral shaft fractures have a good rate of union, despite this fact, still there is a significant rate of nonunion after nonoperative treatment and more often after operative treatment. AIM: The aim of the study is to evaluate the autogenous onlay graft with compression plate for treatment of persistent humeral shaft non-union with failed previous surgery both radiological and functional outcome. MATERIALS AND METHODS: A prospective study on twenty patients having persistent aseptic non-union age between 20 and 60 years old, after failed surgical treatment of fractures humeral shaft in Al-Zahra teaching and Al-Kindy teaching hospitals, while infected nonunion, diabetes mellitus, secondary metastasis, smoking, a
... Show More
The primary components of successful engineering projects are time, cost, and quality. The use of the ring footing ensures the presence of these elements. This investigation aims to find the optimum number of geogrid reinforcement layers under ring footing subjected to inclined loading. For this purpose, experimental models were used. The parameters were studied to find the optimum geogrid layers number, including the optimum geogrid layers spacing and the optimum geogrid layers number. The optimum geogrid layers spacing value is 0.5B. And as the load inclination angle increased, the tilting and the tilting improvement percent for the load inclination angles (5°,10°,15°) are (40%,28%, and 5%) respectively. The reduction percent of the
... Show More
(11)
(7)
The primary components of successful engineering projects are time, cost, and quality. The use of the ring footing ensures the presence of these elements. This investigation aims to find the optimum number of geogrid reinforcement layers under ring footing subjected to inclined loading. For this purpose, experimental models were used. The parameters were studied to find the optimum geogrid layers number, including the optimum geogrid layers spacing and the optimum geogrid layers number. The optimum geogrid layers spacing value is 0.5B. And as the load inclination angle increased, the tilting and the tilting improvement percent for the load inclination angles (5°,10°,15°) are (40%,28%, and 5%) respectively. The reduction percent o
... Show More
(8)
Free-electron lasers (FELs) are disruptive light sources that offer ultrashort pulses, wide spectral tunability, and superior coherence, making them promising candidates for next-generation photonic technologies. However, conventional FEL facilities are large-scale and complex, limiting their integration into communication systems. This study investigates the potential of compact FELs as scalable and versatile light sources for beyond-6G and quantum communication infrastructures. A theoretical framework was established to model resonance conditions, gain dynamics, coherence properties, pulse-duration-limited bit rates, and signal-to-noise ratio (SNR). These models were implemented in MATLAB simulations using parameters representativ
... Show More
The aim of present work is to improve mechanical and fatigue properties for Aluminum alloy7049 by using Nano composites technique. The ZrO2 with an average grain diameter of 30-40 nm, was selected as Nano particles, to reinforce Aluminum alloy7049 with different percentage as, 2, 4, 6 and 7 %. The Stir casting method was used to fabricate the Nano composites materials due to economical route for improvement and processing of metal matrix composites. The experimental results were shown that the adding of zirconium oxide (ZrO2) as reinforced material leads to improve mechanical properties. The best percentage of improvement of mechanical properties of 7049 AA was with 4% wt. of ZrO2 about (7.76% ) for ultim
... Show More
(3)
The photoconductivity and its dependence on light intensity have been investigated in a-Ge20Se80 thin films as a function of temperature between (293–323)K. The result showed that the photoconductivity and photosensitivity increase with increase of annealing temperature. This behavior is interpreted in terms of the dispersive diffusion –controlled recombination of localized electrons and holes.
Abstract Background: The daily usage of maxillofacial prostheses causes them to mechanically deteriorate with time. This study was aimed to evaluate the reinforcement of VST50F maxillofacial silicone by using yttrium oxide (Y2O3) nanoparticles (NPs) to resist aging and mechanical deterioration. Materials and Method: Y2O3 NPs (30–45nm) were loaded into VST50F maxillofacial silicone in two weight percentages (1 and 1.5 wt%), which were predetermined in a pilot study as the best rates for improving tear strength with minimum increase in hardness values. A total of 120 specimens were prepared and divided into the control and experimental groups (with 1 and 1.5 wt% Y2O3 addition). Each group included 40 specimens, 10 specimens for each paramet
... Show More
(4)
(4)
This work describes, selenium (Se) films were deposited on clean glass substrates by dc planar magnetron sputtering technique.The dependence of sputtering deposition rate of Se film deposited on pressure and DC power has been studied. The optimum argon pressure has range (4x10-1 -8x10-2 )mbar. The optical properties such as absorption coefficient (α) was determined using the absorbance and transmission measurement from UnicoUV-2102 PC spectrophotometer, at normal incidence of light in the wavelength range of 200-850 nm. And also we calculated optical constants(refractive index (n), dielectric constant (εi,r), and Extinction coefficient (κ) for selenium films.