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Numerical Simulations of Imaging Extrasolar Planets using Circular and Square Apodize Apertures
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Numerical simulations are carried out to assess the quality of the circular and square apodize apertures in observing extrasolar planets. The logarithmic scale of the normalized point spread function of these apertures showed sharp decline in the radial frequency components reaching to 10-36 and 10-34 respectively and demonstrating promising results. This decline is associated with an increase in the full width of the point spread function. A trade off must be done between this full width and the radial frequency components to overcome the problem of imaging extrasolar planets.

Publication Date
Thu Sep 01 2016
Journal Name
Journal Of Engineering
The Effect of Vehicle Body Shapes on the Near Wake Region and Drag Coefficient: A Numerical Study
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The purpose of this paper is to gain a good understanding about wake region behind the car body due to the aerodynamic effect when the air flows over the road vehicle during its movement. The main goal of this study is to discuss the effect of the geometry on the wake region and the aerodynamic drag coefficient. Results will be achieved by using two different shapes, which are the fastback and the notchback. The study will be implemented by the Computational Fluid Dynamic (CFD) by using STAR-CCM+® software for the simulation. This study investigates the steady turbulent flow using k-epsilon turbulence model. The results obtained from the simulation show that the region of the air separation behind the vehicle

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Publication Date
Sun May 31 2020
Journal Name
Buildings
Experimental and Numerical Study of Behaviour of Reinforced Masonry Walls with NSM CFRP Strips Subjected to Combined Loads
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Near surface mounted (NSM) carbon fibers reinforced polymer (CFRP) reinforcement is one of the techniques for reinforcing masonry structures and is considered to provide significant advantages. This paper is composed of two parts. The first part presents the experimental study of brick masonry walls reinforced with NSM CFRP strips under combined shear-compression loads. Masonry walls have been tested under vertical compression, with different bed joint orientations 90° and 45° relative to the loading direction. Different reinforcement orientations were used including vertical, horizontal, and a combination of both sides of the wall. The second part of this paper comprises a numerical analysis of unreinforced brick masonry (URM) wa

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Publication Date
Tue Jan 01 2013
Journal Name
Journal Of Engineering
Numerical Prediction of Bond-Slip Behavior in Simple Pull-out Concrete Specimen
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In this study the simple pullout concrete cylinder specimen reinforced by a single steel bar was analyzed for bond-slip behavior. Three-dimension nonlinear finite element model using ANSYS program was employed to study the behavior of bond between concrete and plain steel reinforcement. The ANSYS model includes eight-noded isoperimetric brick element (SOLID65) to model the concrete cylinder while the steel reinforcing bar was modeled as a truss member (LINK8). Interface element (CONTAC52) was used in this analysis to model the bond between concrete and steel bar. Material nonlinearity due to cracking and/or crushing of concrete, and yielding of the steel reinforcing bar were taken into consideration during the analysis. The accuracy of this

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Publication Date
Wed May 10 2023
Journal Name
Journal Of Engineering
Numerical Prediction of Bond-Slip Behavior in Simple Pull-Out Concrete Specimens
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In this study the simple pullout concrete cylinder specimen reinforced by a single steel bar was analyzed for bond-slip behavior. Three-dimension nonlinear finite element model using ANSYS program was employed to study the behavior of bond between concrete and plain steel reinforcement. The ANSYS model includes eight-noded isoperimetric brick element (SOLID65) to model the concrete cylinder while the steel reinforcing bar was modeled as a truss member (LINK8). Interface element (CONTAC52) was used in this analysis to model the bond between concrete and steel bar. Material nonlinearity due to cracking and/or crushing of concrete, and yielding of the steel reinforcing bar were taken into consideration during the analysis. The accuracy of t

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Publication Date
Thu Jul 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Comparison of Some Numerical Simulation Techniques for COVID-19 Model in Iraq
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The aim of our study is to solve a nonlinear epidemic model, which is the COVID-19 epidemic model in Iraq, through the application of initial value problems in the current study. The model has been presented as a system of ordinary differential equations that has parameters that change with time. Two numerical simulation methods are proposed to solve this model as suitable methods for solving systems whose coefficients change over time. These methods are the Mean Monte Carlo Runge-Kutta method (MMC_RK) and the Mean Latin Hypercube Runge-Kutta method (MLH_RK). The results of numerical simulation methods are compared with the results of the numerical Runge-Kutta 4th order method (RK4) from 2021 to 2025 using the absolute error, which prove

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Crossref
Publication Date
Thu Feb 01 2024
Journal Name
Journal Of Engineering
Numerical Study of Composite Concrete Castellated Double Channel Beams with Strengthening Techniques
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Current numerical research was devoted to investigating the effect of castellated steel beams without and with strengthening. The composite concrete asymmetrical double hot rolled steel channels bolted back to back to obtain a built-up I-shape form are used in this study. The top half part of the steel is smaller than the bottom half part, and the two parts were connected by bolting and welding. The ABAQUS/2019 program employed the same length and conditions of loading for four models: The first model is the reference without castellated and strengthening; the second model was castellated without strengthened; the third model was castellated and strengthened with reactive powder concrete encased in the

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Publication Date
Thu Apr 27 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Numerical Solutions Of The Nonlocal Problems For The Diffusion Partial Differential Equations
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    In this work, we use the explicit and the implicit finite-difference methods to solve the nonlocal problem that consists of the diffusion equations together with nonlocal conditions. The nonlocal conditions for these partial differential equations are approximated by using the composite trapezoidal rule, the composite Simpson's 1/3 and 3/8 rules. Also, some numerical examples are presented to show the efficiency of these methods.

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Publication Date
Sun Jan 01 1995
Journal Name
المجلة العراقية للاحياء المجهرية
NUMERICAL CHARACTERIZATION OF HALOBACTERIUM SPECIES ISOLATED FROM LOCAL HIGH SALIENT DESERTIFICATION SOILS
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ABSTRACT Fifty extremely halophilic bacteria were isolated from local high salient soils named Al-Massab Al-Aam in south of iraq and were identified by using numerical taxonomy. Fourty strains were belong to the genus Halobacterium which included Hb. halobium (10%). Hb. salinarium (12.5%), Hb.cutirubrum (17.5%), Hb-saccharovorum (12.5%), Hb. valismortis (10%) and Hb. volcanii (37.5%). Growth curves were determined. Generation time (hr) in complex media and logarithmic phase were measured and found to be 10.37±0.59 for Hb. salinarium. 6.49 ± 0.24 for Hb.cutirubrum. 6.70±0.48 for Hb-valismonis, and 11.24 ± 0.96 for Hb. volcanii

Publication Date
Wed May 30 2018
Journal Name
Journal Of Engineering
Numerical Modeling of Water Movement from Buried Vertical Ceramic Pipes through Soils
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The problem of water scarcity is becoming common in many parts of the world, to overcome part of this problem proper management of water and an efficient irrigation system are needed.  Irrigation with a buried vertical ceramic pipe is known as a very effective in the management of irrigation water.  The two- dimensional transient flow of water from a buried vertical ceramic pipe through homogenous porous media is simulated numerically using the HYDRUS/2D software.  Different values of pipe lengths and hydraulic conductivity were selected.  In addition, different values of initial volumetric soil water content were assumed in this simulation as initial conditions.  Different value

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Publication Date
Sun Nov 25 2018
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Numerical Study of Solid Core Photonic Crystal Fibres with Endlessly Single Mode
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       In this work, a solid core photonic crystal fibre (SC-PCF) has been designed with endlessly single mode of which both centerd core and holes in the cladding are organized by circles. The designed SC-PCF has a single solid centerd core which is ringed by a six rings hexagonal cladding. The computation of  SC-PCF is  achieved by using the finite element method (FEM) with perfectly matched layer (PML) boundary condition. All the designed factors like dimensions and distance of both core and cladding areas have varied with an optimized structure. After ending the numerical calculation, the results shows that there are a link between the air hols in the cladding ,  and the different normaliz

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