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Numerical Solution for Two-Sided Stefan Problem
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     In this paper, we consider a two-phase Stefan problem in one-dimensional space for parabolic heat equation with non-homogenous Dirichlet boundary condition. This problem contains a free boundary depending on time. Therefore, the shape of the problem is changing with time. To overcome this issue, we use a simple transformation to convert the free-boundary problem to a fixed-boundary problem. However, this transformation yields a complex and nonlinear parabolic equation. The resulting equation is solved by the finite difference method with Crank-Nicolson scheme which is unconditionally stable and second-order of accuracy in space and time. The numerical results show an excellent accuracy and stable solutions for two test examples.

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Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
The Act Of An Operator
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In this paper we will study some of the properties of an operator by looking at the associated S-act of this operator, and conversely. We look at some operators, like one to one operators, onto operators. On the other hand, we look at some act theoretic concepts, like faithful acts, finitely generated acts, singular acts, separated acts, torsion free acts and noetherian acts. We try to determine what properties of T make the associated S-act has any of these properties.

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Publication Date
Thu Sep 30 2021
Journal Name
Iraqi Journal Of Science
Blow-up Properties of a Coupled System of Reaction-Diffusion Equations
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    This paper is concerned with a Coupled Reaction-diffusion system defined in a ball with homogeneous Dirichlet boundary conditions. Firstly, we studied the blow-up set showing that, under some conditions, the blow-up in this problem occurs only at a single point. Secondly, under some restricted assumptions on the reaction terms, we established the upper (lower) blow-up rate estimates. Finally, we considered the Ignition system in general dimensional space as an application to our results.

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Publication Date
Thu Nov 02 2023
Journal Name
Journal Of Engineering
Studies on the Moisture Dependent Physical Properties of Cowpea
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Cowpea is a very important legume in Nigeria that is being utilized to Substitute high-cost animal protein for low-income people. The knowledge of some physical properties of various moisture contents is of utmost importance in the design of its handling and processing equipment and machinery, which is the aim of this work, which studied the physical properties of IT99K-573-1-1 (SAMPEA14) variety of Cowpea within 8.77 to 21.58 % db moisture content. The properties studied include Major, Intermediate, and Minor diameters, Sphericity, Surface area, Specific gravity, Volume, Bulk density, 50-tap density, 100-tap density, 1250-tap density, seed mass, Angle of repose, Geometric mean diameter, and Arithmetic mean diameter. The

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Publication Date
Fri Sep 30 2022
Journal Name
Iraqi Journal Of Science
Improving the Accuracy of Prayer Times and Calculating Their Change with Geographical Latitudes during the Year 2021 AD
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       The entry time of the prayer in Islam is a prerequisite condition for performing obligatory prayers, and prayer times to be performed in Islam coincides with the time changes of the position of the sun. The elliptical and equatorial coordinates of the sun were calculated for different latitudes. The prayer times for the city of Baghdad were calculated at (latitude = 33.34º N, longitude = 44.43 E) with high accuracy for the year 2021 AD. The results showed that all prayer times are affected by latitude according to each region except (Dhuhr prayer (, it changes with the change of the equation of time, because the equation of time does not depend on latitude, but rather on the sun’s declination, which depends on date. We al

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Publication Date
Wed Mar 01 2023
Journal Name
Journal Of Semiconductors
Bilayer MSe<sub>2</sub> (M = Zr, Hf, Mo, W) performance as a hopeful thermoelectric materials
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Abstract<p>Significant advancements in nanoscale material efficiency optimization have made it feasible to substantially adjust the thermoelectric transport characteristics of materials. Motivated by the prediction and enhanced understanding of the behavior of two-dimensional (2D) bilayers (BL) of zirconium diselenide (ZrSe<sub>2</sub>), hafnium diselenide (HfSe<sub>2</sub>), molybdenum diselenide (MoSe<sub>2</sub>), and tungsten diselenide (WSe<sub>2</sub>), we investigated the thermoelectric transport properties using information generated from experimental measurements to provide inputs to work with the functions of these materials and to determine the </p> ... Show More
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Publication Date
Thu Jul 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Study of Telegraph Equation via He-Fractional Laplace Homotopy Perturbation Technique
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A new technique to study the telegraph equation, mostly familiar as damped wave equation is introduced in this study. This phenomenon is mostly rising in electromagnetic influences and production of electric signals.  The proposed technique called as He-Fractional Laplace technique with help of Homotopy perturbation is utilized to found the exact and nearly approximated results of differential model and numerical example of telegraph equation or damped wave equation in this article. The most unique term of this technique is that, there is no worry to find the next iteration by integration in recurrence relation. As fractional Laplace integral transformation has some limitations in non-linear terms, to get the result of nonlinear term in

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Publication Date
Wed Jan 20 2021
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Hall and Joule's heating Influences on Peristaltic Transport of Bingham plastic Fluid with Variable Viscosity in an Inclined Tapered Asymmetric Channel
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   This paper presents an investigation of peristaltic flow of Bingham plastic fluid in an inclined tapered asymmetric channel with variable viscosity. Taken into consideration Hall current, velocity, thermal slip conditions, Energy equation is modeled by taking Joule heating effect into consideration and by holding assumption of long wavelength and low Reynolds number approximation these equations simplified into couple of non-linear ordinary differential equations that solved using perturbation technique. Graphical analysis has been involved for various flow parameters emerging in the problem. We observed two opposite behaviors for Hall parameter and Hartman number on velocity axial and temperature curves.

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Publication Date
Sat Sep 30 2023
Journal Name
Iraqi Journal Of Science
Impact of Heat Transfer and Inclined MHD on A Non-Uniform Inclined Asymmetrical Channel with Couple Stress Fluid Through A Porous Medium
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     The goal of this study is to investigate the effects of heat transfer on a non-uniform inclined asymmetrical channel with couple stress fluids via a porous medium using incline magnetohydrodynamics. The governing equation is studied while using low Reynolds approximations and long-wavelength assumptions. Mathematical expressions for (pressure gradient), (temperature), (axial velocity), (heat temperature coefficient), and (stream function). A precise set of values for the various parameters in the present model has been used. The mathematical expressions for axial velocity, stream function, pressure gradient, and pressure rise per wavelength have been derived analytically. "MATHEMATICA" is used to present the computational result

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Publication Date
Wed Dec 27 2017
Journal Name
Al-khwarizmi Engineering Journal
The Effect of Restriction Shape On Laminar Natural Convection Heat Transfer In A Vertical Circular Tube
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Natural convection heat transfer is experimentally investigated for laminar air flow in a vertical circular tube by using the boundary condition of constant wall heat flux in the ranges of (RaL) from (1.1*109) to (4.7*109). The experimental set-up was designed for determining the effect of different types of restrictions placed at entry of heated tube in bottom position, on the surface temperature distribution and on the local and average heat transfer coefficients. The apparatus was made with an electrically heated cylinder of a length (900mm) and diameter (30mm). The entry restrictions were included a circular tube of same diameter as the heated cylinder but with lengths of (60cm, 120cm), sharp-edge and

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Publication Date
Tue Mar 31 2015
Journal Name
Al-khwarizmi Engineering Journal
Study on Flow Characteristics and Heat Transfer Behavior Around Different Geometrical Corrugated Extended Surfaces
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Abstract

The current study presents numerical investigation of the fluid (air) flow characteristics and convection heat transfer around different corrugated surfaces geometry in the low Reynolds number region (Re<1000). The geometries are included wavy, triangle, and rectangular. The effect of different geometry parameters such as aspect ratio and number of cycles per unit length on flow field characteristics and heat transfer was estimated and compared with each other. The computerized fluid dynamics package (ANSYS 14) is used to simulate the flow field and heat transfer, solve the governing equations, and extract the results. It is found that the turbulence intensity for rectangular extended surface was larg

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