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Natural and Mixed Convection in Square Vented Enclosure Filled with Metal Foam
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Steady natural and mixed convection flow in a square vented enclosure filled with water-saturated aluminum metal foam is numerically investigated. The left vertical wall is kept at constant temperature and the remaining walls are thermally insulated. Forced convection is imposed by providing an inlet at cavity bottom surface, and a vent at the top surface. Natural convection takes place due to the temperature difference inside the enclosure. Darcy-Brinkman-Forchheimer model for fluid flow and the two-equation of the local thermal non-equilibrium model for heat flow was adopted to describe the flow characteristics within the porous cavity. Numerical results are obtained for a wide range of width of the inlet as a fraction of the height of the enclosure (), the porosity of aluminum foams (, ), Grashof numbers (), and Reynolds number (). Effects of pertinent physical parameters are performed in terms of the flow and temperature fields, as well as the average Nusselt number variations. The results show that the average Nusselt number increases with  and  and decreases with the porosity increasing. The fluid temperature distribution has a little difference from the solid matrix temperature distribution.

 

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Publication Date
Sun Apr 16 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A Fast Estimation of Activation Energy of Low Density Polyethylene (LDPE)
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  A dynamic experimental study of thermal decomposition of low density polyethylene has been carried out with two different heating rates  .As usual , we can determine the activation energy of any polymer using( 3 - 6 ) TGA experiment as minimum , but  in  this work , we estimate the activation energy of  LDPE  using two of  TGA  experiments only

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Publication Date
Tue Apr 24 2018
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Securing digital documents using digital watermarking
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     The intellectual property of digital documents has been protected by using many methods of digital watermarking. Digital documents have been so much of advantages over print documents. Digital documents are less expensive and easy to store, transport, and searched compared to traditional print documents.  But it has its owner limitation too. A simple image editor can be used to modify and make a forged document. Digital documents can be tampered easily. In order to utilize the whole benefits of digital document, these limitations have to overcome these limitations by embedding some text, logo sequence that identifies the owner of the document..

In this research LSB  technique  has been used

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Crossref
Publication Date
Sat Mar 01 2025
Journal Name
Al-iraqia Journal For Scientific Engineering Research
Blue Laser Optical NOMA Communication Applied on Control Drone-to-Underwater Vehicle
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oday deep ocean life has not been discovered by humans including many secret world things to be explored. The researcher has focused on underwater optical wireless communications using various kinds of complex digital Signal processing most of them used in air and starting applied in underwater communication. The Internet of Things (IoT) uses underwater called Internet of Underwater Things (IoUT) applications to explore the underwater world with other devices. However, the difference in concentration between air and water surfaces is not easy making wireless communication more complicated. Visible light passes the water's surface with scattering and distortion inside the water and each color of light has different attenuation the blue laser

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Publication Date
Sat Oct 28 2023
Journal Name
Baghdad Science Journal
Newton-Kantorovich Method for Solving One of the Non-Linear Sturm-Liouville Problems
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Due to its importance in physics and applied mathematics, the non-linear Sturm-Liouville problems
witnessed massive attention since 1960. A powerful Mathematical technique called the Newton-Kantorovich
method is applied in this work to one of the non-linear Sturm-Liouville problems. To the best of the authors’
knowledge, this technique of Newton-Kantorovich has never been applied before to solve the non-linear
Sturm-Liouville problems under consideration. Accordingly, the purpose of this work is to show that this
important specific kind of non-linear Sturm-Liouville differential equations problems can be solved by
applying the well-known Newton-Kantorovich method. Also, to show the efficiency of appl

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Scopus Crossref
Publication Date
Thu Apr 05 2018
Journal Name
Acs Applied Nano Materials
Direct Formation of 2D-MnO<sub><i>x</i></sub> under Conditions of Water Oxidation Catalysis
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We describe the synthesis and characterization of a novel 2D-MnOx material using a combination of HR-TEM, XAS, XRD, and reactivity measurements. The ease with which the 2D material can be made and the conditions under which it can be made implies that water oxidation catalysts previously described as “birnessite-like” (3D) may be better thought of as 2D materials with very limited layer stacking. The distinction between the materials as being “birnessite-like” and “2D” is important because it impacts on our understanding of the function of these materials in the environment and as catalysts. The 2D-MnOx material is noted to be a substantially stronger chemical oxidant than previously noted for other birnessite-like manganese oxi

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Publication Date
Sun Mar 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
Methods of forecasting demandOn the blood substanceApplied study at the National Blood Transfusion Center
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The current research deals with short term forecasting of demand on Blood material, and its' problem represented by increasing of forecast' errors in The National Center for Blood Transfusion because using inappropriate method of forecasting by Centers' management, represented with Naive Model. The importance of research represented by the great affect for forecasts accuracy on operational performance for health care organizations, and necessity of providing blood material with desired quantity and in suitable time. The literatures deal with subject of short term forecasting of demand with using the time series models in order to getting of accuracy results, because depending these models on data of last demand, that is being sta

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Crossref
Publication Date
Mon Feb 20 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Characterization of n-CdO:Mg /p-Si Heterojunction Dependence on Annealing Temperature
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In this research, thin films of CdO: Mg and n-CdO: Mg/ p-Si heterojunction with thickness (500±50) nm have been deposited at R.T (300 K) by thermal evaporation technique. These samples have been annealed at different annealing temperatures (373 and 473) K for one hour. Structural, optical and electrical properties of {CdO: Mg (1%)} films deposited on glass substrate as a function of annealing temperature are studied in detail. The C-V measurement of n-CdO: Mg/ p-Si heterojunction (HJ) at frequency (100 KHz) at different annealing temperatures have shown that these HJ were of abrupt type and the builtin potential (Vbi) increase as the annealing temperature increases. The I-V characteristics of heterojunction prepared under dark case at

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Publication Date
Fri May 15 2015
Journal Name
Journal Of Chemical, Biological And Physical Sciences
Electrical Properties of Tin Sulphide Thin Films
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In this study, SnS thin films were deposited onto glass substrate by thermal evaporation technique at 300K temperature. The SnS films have been prepared with different thicknesses (100,200 &300) nm. The crystallographic analysis, film thickness, electrical conductivity, carrier concentration, and carrier mobility were characterized. Measurements showed that depending on film thickness. The D.C. conductivity increased with increase in film thickness from 3.720x10-5 (Ω.cm)-1 for 100 nm thickness to 9.442x10-4 (Ω.cm)-1 for 300 nm thicknesses, and the behavior of activation energies, hall mobility, and carrier concentration were also studied.

Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
Performance Analysis of Four Conceptual Designs for the Air Based Photovoltaic / Thermal Collectors
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The  thermal  and  electrical  performance  of  different  designs  of  air  based  hybrid photovoltaic/thermal collectors is investigated experimentally and theoretically. The circulating air is used to cool PV panels and to collect the absorbed energy to improve their performance. Four different collectors have been designed, manufactured and instrumented namely; double PV panels without cooling (model I), single duct double pass collector (model II), double duct single pass (model III), and single duct single pass (model IV) . Each collector consists of: channel duct, glass cover, axial fan to circulate air and two PV panel in parallel connection. The temperature of the upper and

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Publication Date
Sun Sep 01 2013
Journal Name
Baghdad Science Journal
Theoretical Study of Thermal Cracking For Acenaphthylene Molecule
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Density Functional Theory (DFT) calculations were carried out to study the thermal cracking for acenaphthylene molecule to estimate the bond energies for breaking C8b-C5a , C5a-C5 , C5-C4 , and C5-H5 bonds as well as the activation energies. It was found that for C8b-C5a , C5-C4 , and C5-H5 reactions it is often possible to identify one pathway for bond breakage through the singlet or triplet states. The atomic charges , dipole moment and nuclear – nuclear repulsion energy supported the breakage bond .Also, it was found that the activation energy value for C5-H5 bond breakage is lower than that required for C8b-C5a , C5a-C5 , C5-C4 bonds which refer to C5-H5 bond in acenaphthylene molecule are weaker than C8b-C5a , C5a-C5 , C5-C

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