In this paper, we built a mathematical model for convection and thermal radiation heat transfer of fluid flowing through a vertical channel with porous medium under effects of horizontal magnetic field (MF) at the channel. This model represents a 2-dimensional system of non-linear partial differential equations. Then, we solved this system numerically by finite difference methods using Alternating Direction Implicit (ADI) Scheme in two phases (steady state and unsteady state). Moreover, we found the distribution and behaviour of the heat temperature inside the channel and studied the effects of Brinkman number, Reynolds number, and Boltzmann number on the heat temperature behaviour. We solved the system by building a computer program using MATLAB.
In the present work, Uranium (238U), Thorium (232Th) and Potassium (40K) specific activity concentration in (Bq/kg) was measured in five different types for wheat flours that are available in the Iraqi markets. The gamma spectrometry method with an NaI (Tl) detector has been used for radiometric measurements. Calculations of radium equivalent activity, annual effective dose equivalent, external hazard index (Hex), internal hazard index (Hin), representing gamma index and gamma dose rate in all flour samples were 17.98132 Bq/kg, 0.0100334, 0.04502, 0.04857, 0.06872, 0.125883 and 8.181244 respectively. It is found that the average of specific activity concentration of wheat flour sam
... Show MoreThe effect of 0.662MeV gamma radiation on the optical properties of the CdTe thin films was studied. 300nm thickness of CdTe samples were irradiated with doses (10, 20, 30,60krad) in room temperature. The absorption spectra for all the samples were recorded using UV- Visible spectrometer in order to calculate the energy gap, width of localized states and optical constants(refractive index, extinction coefficient, real and imaginary parts of dielectric constant). The optical energy gap was found to decrease from (1.53 to 1.48 eV), while the width of localized states increased from (1.34 to 1.49 eV) with the increasing of radiation dose. The behavior of energy gap with the irradiation dose makes the material a good candidate for dosimetry
... Show MoreA numerical study of the double-diffusive laminar natural convection in a right triangular solar collector has been investigated in present work. The base (absorber) and glass cover of the collector are isothermal and isoconcentration surfaces, while the vertical wall is considered adiabatic and impermeable. Both aiding and opposing buoyancy forces have been studied. Governing equations in vorticity-stream function form are discretized via finite-difference method and are solved numerically by iterative successive under relaxation (SUR) technique. Computer code for MATLAB software has been developed and written to solve mathematical model. Results in the form of streamlines, isotherms, isoconcentration, average Nusselt, and average Sherw
... Show MoreIn this study a combination of two basics known methods used to daily prediction of solar insolation in Baghdad city, Iraq, for the first time, the harmonic and the classical linear regression analyses, thus it is called HARLIN model. The resulted prediction data compared with basics data for Baghdad city for two years (2010-2011), where the model showed a great success application in the accurate results, compared with the linear famous and well known model which is used the classical linear Angstrom equations with various formulations in many previous studies.
The effect of 0.66 µeV gamma radiation on the structural and optical properties of the CdTe thin films prepared by thermal evaporation at thickness 350nm, The samples were irradiated with time (50 h and 79h) at room temperature. The absorption spectra for all the samples were recorded using UV-VIS spectrometer in order to calculate the energy gap, refractive index and others parameter . The optical energy gap was found decrease from (1.9 to 1.67) eV.
The effects of solar radiation pressure at several satellite (near Earth orbit satellite, low Earth orbit satellite, medium Earth orbit satellite and high Earth orbit satellite ) have been investigated. Computer simulation of the equation of motion with perturbations using step-by-step integration (Cowell's method) designed by matlab a 7.4 where using Jacobian matrix method to increase the accuracy of result.
In this research measuring the radioactivity of the soil batteries plant in Waziriya in Baghdad city ,where the collection of 60 samples from different locations and depth between(10cm-50cm)by using γ-ray spectrometer technique and sodium iodide detector to measure the activityof radiation of elements radiation ,where the results showed that there are aradioctivety of natural isotopes refers to the chains of U-238and Th-232and K-40and Cs-137the results show that ahigh concentration of Pb-214,Pb-212 within the permissible internationally values ,also the valuable parameters of radium and the external and internal hazard and the dose effect where its found to be permissible internationally.
The present paper concerns with peristaltic analysis of MHD viscous fluid in a two dimensional channel with variable viscosity through a porous medium under the effect of slip condition. Along wave length and low Reynolds number assumption is used in the problem formulation. An analytic solution is presented for the case of hydrodynamic fluid while for magneto hydrodynamic fluid a series solution is obtained in the small power of viscosity parameter. The salient features of pumping and trapping phenomena are discussed in detail through a numerical integration. The features of the flow characteristics are analyzed by plotting graphs and discussed in detail. When .
This paper examines the finding of spacewise dependent heat source function in pseudoparabolic equation with initial and homogeneous Dirichlet boundary conditions, as well as the final time value / integral specification as additional conditions that ensure the uniqueness solvability of the inverse problem. However, the problem remains ill-posed because tiny perturbations in input data cause huge errors in outputs. Thus, we employ Tikhonov’s regularization method to restore this instability. In order to choose the best regularization parameter, we employ L-curve method. On the other hand, the direct (forward) problem is solved by a finite difference scheme while the inverse one is reformulated as an optimization problem. The
... Show MoreIn this paper, the oscillatory and nonoscillatory qualities for every solution of fourth-order neutral delay equation are discussed. Some conditions are established to ensure that all solutions are either oscillatory or approach to zero as . Two examples are provided to demonstrate the obtained findings.