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ijs-4617
Linear and Non-Linear Stability Analysis for Thermal Convection in A Bidispersive Porous Medium with Thermal Non-Equilibrium Effects: Linear and non-linear stability analysis
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     The linear instability and nonlinear stability analyses are performed for the model of bidispersive local thermal non-equilibrium flow. The effect of local thermal non-equilibrium on the onset of convection in a bidispersive porous medium of Darcy type is investigated.  The temperatures in the macropores and micropores are allowed to be different. The effects of various interaction parameters on the stability of the system are discussed. In particular, the effects of the porosity modified conductivity ratio parameters,  and , with the inter-phase momentum transfer parameters and, on the onset of thermal Convection are also considered. Furthermore, the nonlinear stability boundary is found to be below the linear instability threshold. The numerical results are presented for free-free boundary conditions.

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Publication Date
Sun Apr 16 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Structural and Surface Morphology Properties of Aluminum Doped CdO Thin Films Prepared by Vacuum Thermal Evaporation Technique.
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   Undoped and Al-doped CdO thin films have been prepared by vacuum thermal evaporation  on  glass  substrate  at  room  temperature  for  various  Al  doping ratios (0.5, 1 and 2)wt.% . The films are characterized by XRD and AFM surface morphology properties. XRD analysis showed that CdO:Al films are highly polycrystalline and exhibit cubic crystal structure of lattice constant averaged to 0.4696 nm with (111) preferred orientation. However, intensity of all peaks rapidly decreases which indicates that the crystallinity decreases with the increase of Al dopant. The grain size decreases with Al content (from 60.81 to 48.03 nm). SEM and AFM were applied to study the morphology an

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Publication Date
Tue Jan 01 2019
Journal Name
Aip Conference Proceedings
Studying some of mechanical properties (tensile, impact, hardness) and thermal conductivity of polymer blend reinforce by magnesium oxide
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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
The Bifurcation Analysis of Food Web Prey- Predator Model with Toxin
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Abstract<p>Local and global bifurcations of food web model consists of immature and mature preys, first predator, and second predator with the current of toxicity and harvesting was studied. It is shown that a trans-critical bifurcation occurs at the equilibrium point <italic>E</italic> <sub>0</sub>, and it revealed the existence of saddle-node bifurcation occurred at equilibrium points <italic>E</italic> <sub>1</sub>, <italic>E</italic> <sub>2</sub> and <italic>E</italic> <sub>3</sub>. At any point, the occurrence of bifurcation of the pitch for</p> ... Show More
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Publication Date
Mon Jun 17 2019
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Determination of Manganese (II) using Flow Injection Analysis with Chemiluminescence detection
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The determination of manganese (II) using flow injection analysis with chemiluminescence detection was investigated. Mn2+ in sample solutions injected into a carrier stream of sodium bismuthate (NaBiO3) were oxidised to form MnO4- ions which were capable of producing luminescence after reaction with luminol/KOH in a flow cell. The linear range of the system is from 20 to 80 mg/L with a detection limit 8 mg/L. The proposed system is suitable for determination of Mn2+ in steel alloys after dissolution, filtration and dilution at a rate of approximately 60 samples per hour with a relative standard deviation (RSD)1.2%. Statistical comparison between the proposed system and standard spectrophotometric method revealed that there is no signific

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Publication Date
Sat Jan 01 2022
Journal Name
Journal Of The Mechanical Behavior Of Materials
Analysis of concrete beams reinforced by GFRP bars with varying parameters
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Abstract<p>Structural buildings consist of concrete and steel, and these buildings have confronted many challenges from various aggressive environments against the materials manufactured from them. It contains high water levels and buildings whose concrete cover may be damaged and thus lead to the deterioration and corrosion of steel. It was important to have an alternative to steel, such as the glass fiber reinforced polymer (GFRP), which is distinguished by its great effectiveness in resisting corrosion, as well as its strong tensile resistance. Still, one of its drawbacks is that it has a low modulus of elasticity. This research article aims to conduct a numerical study using the nonlinear fi</p> ... Show More
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Publication Date
Mon May 23 2022
Journal Name
The International Journal Of Artificial Organs
Quantitative analysis and control of the torque profile of the upper limb using a kinetic model and motion measurements
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This paper investigates a new approach to the rapid control of an upper limb exoskeleton actuator. We used a mathematical model and motion measurements of a human arm to estimate joint torque as a means to control the exoskeleton’s actuator. The proposed arm model is based on a two-pendulum configuration and is used to obtain instantaneous joint torques which are then passed into control law to regulate the actuator torque. Nine subjects volunteered to take part in the experimental protocol, in which inertial measurement units (IMUs) and a digital goniometer were used to measure and estimate the torque profiles. To validate the control law, a Simscape model was developed to simulate the arm model and control law in which measurem

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Publication Date
Sun Oct 02 2011
Journal Name
The Iraqi Journal Of Agricultural Sciences
AN ECONOMIC ANALYSIS OF PRODUCTION AND CONSUMPTION OF SUGAR CANE AND SUGAR BEET IN IRAQ
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In spite of economic importance of sugar cane and sugar beet as they described as industrial crops they still face decreasing rates of production and productivity in Iraq , and their production was not able to satisfy the local industrial demands for sugar . Thus this study aimed at studying and analyzing, production and productivity of sugar cane and sugar beet in Iraq and this has been done by using non serial data that can be obtained from official offices in Iraq . The area and production of sugar cane in Iraq recorded positive annual growth rates during 1970- 1978 which were 6% and 5% consequently , while the productivity of sugar cane recorded at the same duration of time negative annual growth rate which was 1% , while they recorded

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Publication Date
Tue Nov 30 2021
Journal Name
Iraqi Journal Of Science
Measurement and Analysis of Natural Radioactive Elements in Salty Sediments from Central and Southern Iraq
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Purification of fifteen NaCl samples from natural and different area in the middle and south of Iraq are prepared  and studied the structural characteristics of samples by powder X-ray diffraction analysis at 𝛌=1.542Ã…. The present work considered the specific activities of naturally occurring radioactive materials in salt samples, which are measured and analyzed using high resolution HPGe system. Also, the radiological parameters have been considered in this work. The average specific concentration (in Bq.kg-1) of the salt samples is found 16.864.92 for 226Ra, 5.972.05 for 232Th and 9.852.8 for 40K, respectively, which are below the national levels, 40Bq.kg-1, 30Bq.k

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Publication Date
Tue Sep 11 2018
Journal Name
Iraqi Journal Of Physics
The antibacterial activity of indium oxide thin film prepared by thermal deposition
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Indium oxide In2O3 thin films fabricated using thermal evaporation of indium metal in vacuum on a glass substrate at 25oC using array mask, after deposition the indium films have been subjected to thermal oxidation at temperature 400 °C for 1h. The results of prepared Indium oxide reveal the oxidation method as a strong effect on the morphology and optical properties of the samples as fabricated. The band gap (Eg) of In2O3 films at 400 °C is 2.7 eV. Then, SEM and XRD measurements are also used to investigate the morphology and structure of the indium oxide In2O3 thin films. The antimicrobial activity of indium oxide In2O3 thin films was assessed against gram-negative bacterium using inhibition zone of bacteria which improved higher ina

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Publication Date
Thu May 25 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Phonon Confinement Effect on Lattice Thermal Conductivity of Zn4Sb3 Quantum Well Structure
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We have theoretically investigated the in-plane lattice thermal conductivity of Zn4Sb3single quantum well structure taking into account spatial confinement of phonons. The calculations were carried out for free-surface quantum wells with thickness 8.5nm in the room temperature. We show that the lattice thermal conductivity is a significant reduce. The reduction is mostly due to the drop in the average group velocity caused by the spatial confinement of acoustic phonons and the corresponding increase in phonon relaxation rates. The predicted decrease is important for the anticipated applications of Zn4Sb3 nanostructure materials for room-temperature thermoelectric devices. Our theoretical results are in a good agreement with available exp

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