Simulation of free convection heat transfer in a square enclosure induced by heated thin plate is represented numerically. All the enclosure walls have constant temperature lower than the plate’s temperature. The flow is assumed to be two-dimensional. The discretized equations were solved stream function, vorticity, and energy equations by finite difference method using explicit technique and Successive Over- Relaxation method. The study was performed for different values of Rayleigh number ranging from 103 to 105 for different angle position of heated thin plate(0°, 45°, 90°). Air was chosen as a working fluid (Pr = 0.71). Aspect ratio of center of plate to the parallel left wall A2 take a constant and is equal to 0.5. The effect of the angle position of the heated thin plate on heat transfer and flow were addressed. With the increase of Rayleigh number heat transfer rate increased in both vertical and horizontal position of the plate. For the vertical situation (γ=90°) of thin plate, heat transfer becomes more enhanced than for the horizontal situation (γ=0°) and the inclined situation (γ=45°) especially when the value of aspect ratio A1 is equal to 0.25.
In this experimental study, which was carried out in photonics laboratory at Strathclyde University, UK, dynamics of a multi-Quantum well semiconductor active medium laser, was studied. This is in order to study its emission stability and pulse shape development under the influence of strong optical feedback level with different deriving currents, in the free space transmission medium. An external stable resonator was constructed by inserting high reflectivity dielectric mirror outside the laser output, 20 cm apart from it, which is an extralarge external cavity. Controlling the reflected back optical power was done by using a nonpolarized (50:50) beam splitter. The external resonator supported by focusing (plano-convex) lens in order to
... Show MoreThe present study aims to detect CTX-M-type ESBL from Escherichia coli clinical isolates and to analyze their antibotic susceptibility patterns. One hundred of E. coli isolates were collected from different clinical samples from a tertiary hospital. ESBL positivity was determined by the disk diffusion method. PCR used for amplification of CTX-M-type ESBL produced by E. coli. Out of 100 E. coli isolates, twenty-four isolates (24%) were ESBL-producers. E. coli isolated from pus was the most frequent clinical specimen that produced ESBL (41.66%) followed by urine (34.21%), respiratory (22.23%), and blood (19.05%). After PCR amplification of these 24 isolates, 10 (41.66%) isolates were found to possess CTX-M genes. The CTX-M type ESBL
... Show MoreIn this study, the thermal buckling behavior of composite laminate plates cross-ply and angle-ply all edged simply supported subjected to a uniform temperature field is investigated, using a simple trigonometric shear deformation theory. Four unknown variables are involved in the theory, and satisfied the zero traction boundary condition on the surface without using shear correction factors, Hamilton's principle is used to derive equations of motion depending on a Simple Four Variable Plate Theory for cross-ply and angle-ply, and then solved through Navier's double trigonometric sequence, to obtain critical buckling temperature for laminated composite plates. Effect of changing some design parameters such as, ortho
... Show MoreThe free zone or the free economy cities are cities with classification and functional specificity, although the history of the concept of these areas has been It dates back to distant eras, but the intellectual and philosophical construction with the support of intellectual approaches, the most important of which is globalization contributed to its rapid spread globally and taking a variety of forms and models. With the diversity of its formulas and objectives countries have competed in adopting the establishment of these areas, meanwhile The influence of related trends affected the contemporary formation of these sites. Therefore ,the research was directed focus on the importance of adopting a set of common indicators (collection
... Show MoreThe unsteady state laminar mixed convection and radiation through inclined
cylindrical annulus is investigated numerically. The two heat transfer mechanisms of
convection and radiation are treated independently and simultaneously. The outer
cylinder was kept at a constant temperature while the inner cylinder was heated with
constant heat flux. The study involved numerical solution of the governing equations
which are continuity, momentum and energy equations using finite difference method
(FDM), where the body fitted coordinate system (BFC) was used to generate the grid
mesh for computational plane. A computer program (Fortran 90) was built to calculate
the bulk Nusselt number (Nub) after reaching steady state con
The goal of this experimental study is to determine the effects of different parameters (Flow rate, cuttings density, cuttings size, and hole inclination degree) on hole cleaning efficiency. Freshwater was used as a drilling fluid in this experiment. The experiments were conducted by using flow loop consist of approximately 14 m (46 ft) long with transparent glass test section of 3m (9.84 ft.) long with 4 inches (101.6 mm) ID, the inner metal drill pipe with 2 inches (50.8 mm) OD settled with eccentric position positive 0.5. The results obtained from this study show that the hole cleanings efficiency become better with high flow rate (21 m3/hr) and it increase as the hole inclination angles increased from 60 to 90 degree due to dominated
... Show MoreBackground: One of the most common problems that encountered is postburn contracture which has both functional and aesthetic impact on the patients. Various surgical methods had being proposed to treat such problem. Aim: To evaluate the effectiveness of square flap in management of postburn contracture in several part of the body. Patients and methods: From April 2019 to June 2020 a total number of 20 patients who had postburn contracture in various parts of their body were subjected to scar contracture release using square flap. The follow up period was ranging between 6 months to 12 months. Results: All of our patients had achieved complete release of their band with maximum postoperative motion together with accepted aesthetic outcome. A
... Show MoreThe topic of the research dealt with the image of Iraq in the British press based on a sample of the newspapers (The Guardian and the Daily Telegraph), which are among the most important and largest newspapers in the United Kingdom and the world, because of its active role in guiding local and international public opinion towards important issues and events, Since these two newspapers are interested in the accuracy of sensitive political topics, the message aimed at knowing the media image that these two newspapers painted about Iraq in the period that was limited to the first quarter of 2019, and also to know the nature of the contents promoted by these newspapers about the Iraqi reality, The method of content analysis was used as an ap
... Show MoreThe solidification process in a multi-tube latent heat energy system is affected by the natural convection and the arrangement of heat exchanger tubes, which changes the buoyancy effect as well. In the current work, the effect of the arrangement of the tubes in a multi-tube heat exchanger was examined during the solidification process with the focus on the natural convection effects inside the phase change material (PCM). The behavior of the system was numerically analyzed using liquid fraction and energy released, as well as temperature, velocity and streamline profiles for different studied cases. The arrangement of the tubes, considering seven pipes in the symmetrical condition, are assumed at different positions in the system, i
... Show MoreThe air flow pattern in a co-current pilot plant spray dryer fitted with a rotary disk atomizer was determined experimentally and modelled numerically using Computational Fluid Dynamics (CFD) (ANSYS Fluent ) software. The CFD simulation used a three dimensions system, Reynolds-Average Navier-Stokes equations (RANS), closed via the RNG k −ε turbulence model. Measurements were carried out at a rotation of the atomizer (3000 rpm) and when there is no rotation using a drying air at 25 oC and air velocity at the inlet of 5 m/s without swirl. The air flow pattern was predicted experimentally using cotton tufts and digital anemometer. The CFD simulation predicted a downward central flowing air core surrounded by a slow
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