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Numerical investigation of natural convection in a square enclosure partially filled with horizontal layers of a porous medium
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Abstract<p>Two‐dimensional buoyancy‐induced flow and heat transfer inside a square enclosure partially occupied by copper metallic foam subjected to a symmetric side cooling and constant heat flux bottom heating was tested numerically. Finite Element Method was employed to solve the governing partial differential equations of the flow field and the Local Thermal Equilibrium model was used for the energy equation. The system boundaries were defined as lower heated wall by constant heat flux, cooled lateral walls, and insulated top wall. The three parameters elected to conduct the study are heater length (7 ≤ <italic>ζ</italic> ≤ 20 cm), constant heat flux (150 ≤ <italic>q</italic>″ ≤ 600 W m<sup>−</sup><sup>2</sup>), and porous material thickness (5 ≤ <italic>H</italic> ≤ 20 cm). The porous material used was the copper metal foam of porosity = 0.9 and pore density PPI = 10, and saturated with a fluid of Prandtl number = 0.7. On the basis of the results obtained, it was concluded that at the porous layer thickness = 5 cm, the rate of heat transferred was (74.6%) higher than when the layer height was 20 cm (the cavity is fully filled) and at the same thickness it was found that the heat rate is (51.4%) higher than when using the half filling (<italic>H</italic> = 10 cm). Further, the local and mean Nusselt number is maximum when using the largest heater size and smallest porous layer thickness. Finally, better circulation and convective modes were observed at high values of heat flux.</p>
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Publication Date
Mon Mar 15 2021
Journal Name
The Journal Of Legal And Social Sciences
Limitations on the authority of a judge in case-law ( France as a model )
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When exercising their authority in the jurisprudence, judges are subject to a set of restrictions that they must adhere to, as they do not want their jurisprudence to be accepted and welcomed by law practitioners in general, and legal scholars in particular, and in contrast to it, the arrows of criticism and defamation will extend to that jurisprudence, and then they will have to reverse them . Perhaps the most important of those restrictions imposed on judges is their observance of justice between the parties to the lawsuit through their lack of bias for one of the parties at the expense of the other, in addition to their observance of public order and public morals, as well as their observance of the legal texts that they work under its u

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Building a Reliable Steganography System Using Random Key in a spatial Domain of Image
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With time progress importance of hiding information become more and more and all steganography applications is like computer games between hiding and extracting data, or like thieves and police men always thieve hides from police men in different ways to keep him out of prison. The sender always hides information in new way in order not to be understood by the attackers and only the authorized receiver can open the hiding message. This paper explores our proposed random method in detail, how chooses locations of pixel in randomly , how to choose a random bit to hide information in the chosen pixel, how it different from other approaches, how applying information hiding criteria on the proposed project, and attempts to test out in code, and

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Publication Date
Sun Jan 02 2022
Journal Name
Journal Of The College Of Languages (jcl)
A Pragmatic Analysis of Illocutionary Act in a Selected Presidential Speech on COVID-19
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     This paper aims at studying the illocutionary speech acts: direct and indirect to show the most dominant ones in a presidential speech delivered by the USA president. The speech is about the most critical health issue in the world, COVID-19 outbreak.  A descriptive qualitative study was conducted by observing the first speech delivered by president Trump concerning coronavirus outbreak and surveying the illocutionary acts: directive, declarative, commissive, expressive, and representative. Searle's (1985) classification of illocutionary speech acts is adopted in the analysis.

     What are the main types of the illocutionary speech acts performed by Trump in his speech?; Why does

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Publication Date
Fri Jan 11 2019
Journal Name
Iraqi Journal Of Physics
Porous silicon prepared by photo electrochemical etching assisted by laser
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Porous silicon (PS) layers are prepared by anodization for
different etching current densities. The samples are then
characterized the nanocrystalline porous silicon layer by X-Ray
Diffraction (XRD), Atomic Force Microscopy (AFM), Fourier
Transform Infrared (FTIR). PS layers were formed on n-type Si
wafer. Anodized electrically with a 20, 30, 40, 50 and 60 mA/cm2
current density for fixed 10 min etching times. XRD confirms the
formation of porous silicon, the crystal size is reduced toward
nanometric scale of the face centered cubic structure, and peak
becomes a broader with increasing the current density. The AFM
investigation shows the sponge like structure of PS at the lower
current density porous begi

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Publication Date
Sat Jan 01 2011
Journal Name
Iraqi Journal Of Physics
Natural radioactivity survey in Al-Jabal Al-Gharbi Mountain Region Libya
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The measurement of natural radioactivity in a given region or country is essential to provide a reference base-line map to follow up a possible variation in future. In order to perform such measurement, the natural radioactivity was measured in different locations. The locations (50 sites) were distributed over Al-Jabal Al-Gharbi Mountain, starting from the city Al-Azeeziah in the eastern part to Wazen on the Tunisian border in the west. The measurements showed obvious variation from one site to another. The levels were fluctuating from (12.8 counts/minute) in Bir-Ayad to (45.7 counts/minute) in Gherian.
In order to investigate the cause for such variation, samples were collected from (27) sites for detailed study. The levels of natur

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Publication Date
Sat Nov 24 2018
Journal Name
Open Access Macedonian Journal Of Medical Sciences
Outcomes of Operative Management of 96 Cases with Traumatic Retroperitoneal Hematoma: A Single-Institution Experience
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AIM: To analyse our experiences in the management of traumatic retroperitoneal hematoma (RPH), highlighting the various challenges faced and to report on the outcome of these patients. METHODS: From May 2014 to May 2017, all patients with traumatic RPH who underwent surgical treatment were retrospectively analysed. The kind of injury, intraoperative findings, sites of hematoma, postoperative morbidity and the overall outcomes were recorded. RESULTS: Ninety-six patients; 53 with blunt trauma and 43 with penetrating injury, were included in this study. The centre-medial hematoma was observed in 24 (25%) patients, lateral hematoma in 46 (47.9%) patients, pelvic hematoma in 19 (19.8%) patients, and multiple zone hematomas in

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Publication Date
Wed Jan 01 2014
Journal Name
Journal Of Biology, Agriculture And Healthcare
Histopathological Changes of Some Internal Organs of Mice Injected with Exotoxin a at Low Concentrations
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Abstract Exotoxin A is the most lethal virulence factor produced by Pseudomonas aeruginosa. It inhibits elongation factor-2 by ADP-ribosylation of EF2. This causes stop of the elongation of polypeptides. In recent study, the effect of low concentration of exotoxin A on some important internal organs of mice was studied. Four groups white mice were injected intraperitonialy with pure exotoxin A in the following manner 0.1, 0.2, 0.3, 0.4 ng\ animals. One mouse receives normal saline inrtaperitonialy as a control. After 72 hours the mice were killed and four organs were taken, liver, spleen, lung and heart from each killed mice. Histological sections were made from each organ and stained with hematoxylin and eosin stain then examined under mic

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Publication Date
Thu Jan 12 2023
Journal Name
Mathematics
Dynamical Behavior of a Cancer Growth Model with Chemotherapy and Boosting of the Immune System
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In this study, we set up and analyze a cancer growth model that integrates a chemotherapy drug with the impact of vitamins in boosting and strengthening the immune system. The aim of this study is to determine the minimal amount of treatment required to eliminate cancer, which will help to reduce harm to patients. It is assumed that vitamins come from organic foods and beverages. The chemotherapy drug is added to delay and eliminate tumor cell growth and division. To that end, we suggest the tumor-immune model, composed of the interaction of tumor and immune cells, which is composed of two ordinary differential equations. The model’s fundamental mathematical properties, such as positivity, boundedness, and equilibrium existence, are exami

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Publication Date
Sat Oct 28 2023
Journal Name
Baghdad Science Journal
A Comparative Study of the Photostabilization of Polyvinyl Chloride with Nano and Micro Nickel Oxide
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NiO nanoparticle synthesis by chemical method and characterized by XRD with crystal size 11.72
nm and grain size 13 nm from FESEM image also NiO micro used ,two NiO as an additive to evaluate the
possibility of producing photodegradable polymers, the practical application of solid-phase photocatalytic
degradation of polyvinyl chloride (PVC- NiO composite films) was investigated. PVC has a negative impact
on the environment since its polymer degrades slowly, yet it has a wide range of industrial applications and
the amount used shows no evidence of diminishing use. Thus, a synthesis of modified PVC- NiO micro and
nano has been studied with 0, 50, 100, 150, 200, 250, and 300 (hours) as irradiation time a

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Publication Date
Wed Sep 01 2021
Journal Name
Journal Of Applied Mathematics
The Dynamics of a Tritrophic Leslie-Gower Food-Web System with the Effect of Fear
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The avoidance strategy of prey to predation and the predation strategy for predators are important topics in evolutionary biology. Both prey and predators adjust their behaviors in order to obtain the maximal benefits and to raise their biomass for each. Therefore, this paper is aimed at studying the impact of prey’s fear and group defense against predation on the dynamics of the food-web model. Consequently, in this paper, a mathematical model that describes a tritrophic Leslie-Gower food-web system is formulated. Sokol-Howell type of function response is adapted to describe the predation process due to the prey’s group defensive capability. The effects of fear due to the predation process are considered in the first two levels

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