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ijcpe-347
PARAMETRIC STUDY OF NATURAL CONVECTIVE AND RADIATIVE HEAT TRANSFER IN INCLINED CYLINDRICAL ANNULI
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The unsteady state laminar mixed convection and radiation through inclined
cylindrical annulus is investigated numerically. The two heat transfer mechanisms of
convection and radiation are treated independently and simultaneously. The outer
cylinder was kept at a constant temperature while the inner cylinder was heated with
constant heat flux. The study involved numerical solution of the governing equations
which are continuity, momentum and energy equations using finite difference method
(FDM), where the body fitted coordinate system (BFC) was used to generate the grid
mesh for computational plane. A computer program (Fortran 90) was built to calculate
the bulk Nusselt number (Nub) after reaching steady state condition for fluid Prandtl
number fixed at (Pr =0.7) (for air) with radius ratio ( =1.5, 2.6, 5.0), Rayleigh number
(0≤Ra≤103),Reynolds number (50≤Re≤2000), dimensionless heat generation (0≤Q≤10),
Conduction-Radiation parameter (0≤N≤10), optical thickness (0 ≤ t

≤ 10) and different
annulus inclination with horizontal plane (0°≤δ≤90°). For the range of parameters
considered, results show that radiation enhance heat transfer. It is also indicated in the
results that Nu increase with the increasing of inclination angle δ, Ra, Re, and Q. The
correlation equations are concluded to describe the radiation effect.
Comparison of the result with the previous work shows a good agreement.

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Publication Date
Mon Jan 01 2024
Journal Name
Proceedings Of The International Conference On Research Advances In Engineering And Technology - Itechcet 2022
Suitability of Iraqi legal system for building operation transfer contract in infrastructure construction projects
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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
Investigating of Charge Transfer in Cu/F8 Using Donor-Acceptor Model due Quantum Transition
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in this paper, we study and investigate a simple donor-acceptor model for charge transfer formation using a quantum transition theory. The transfer parameters which enhanced the charge transfer and the rate of the charge transfer have been calculated. Then, we study the net charge transfer through interface of Cu/F8 contact devices and evaluate all transfer coefficients. The charge transfer rate of transfer processes is found to be dominated in the low orientation free energy and increased a little in decreased potential at interface comparison to the high potential at interface. The increased transition energy results in increasing the orientation of Cu to F8. The transfer in the system was more active when the system has large driving for

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Publication Date
Thu Sep 30 2021
Journal Name
Iraqi Journal Of Science
Measurement of Specific Activity of Natural Radioactive Materials and Cs-137 in Soil Samples for Some Areas in Al-Doura City in Baghdad Governorate
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   In the present work, radium (226Ra), thorium (232Th), potassium (40 K), and cesium (137Cs) (Bq/kg) was measured for 24 soil samples of some districts of Al-Doura city in Baghdad governorate. The gamma spectrometry method with NaI (Tl) detector was used for radiometric measurements. The average values of specific activity for   226Ra, 232Th, 40K and 137Cs in soil samples were 38.03, 42.48, 16.34 and 2.76 Bq/kg, respectively. The radiation indicators were measured and the average values recorded were 100 Bq/kg, 44.6 nGy/h, 0.27 Bq/kg, 0.373 Bq/kg, 0.219 mSv/y, 0.055 mSv/y and 0.689 Bq/kg for the parameters of radium equivalent act

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Publication Date
Thu Oct 20 2022
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Fabrication of Natural Gelcoats (Epoxy/ Pumpkin Peels Fibers) Composites with High Mechanical and Thermal Properties
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     Pumpkin waste powder was used as a coloring and strengthening filler in epoxy to prepare a natural gelcoat . The Pumpkin powder was mixed with different weight ratios (1, 2, 3, 4, 5, 6, 7, and 8%) to the epoxy matrix to select the best value of powder addition. The effect of the pumpkin particle size on the mechanical properties (impact, flexural, hardness, and wear loss) using two different sizes (2.5 and 1.25 microns) was studied. The impact strength increased from (10.09 KJ/ m2) for neat epoxy to (14.79 KJ/ m2) for epoxy with  1% of micron pumpkin fibers ( MPF) with particle size 2.5 micrometer and (14.21 KJ/ m2) for epoxy with 4% (1.25 MPF), flexural strength increased from (41.94 MPa) for n

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Publication Date
Sun Dec 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Prevention of Scale Formation in Heat Exchanger Pipes by Using Magnetic Field
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The possibility of using the magnetic field technique in prevention of forming scales in heat exchangers pipes using
hard water in heat transfer processes, also the studying the effective and controllable parameters on the mechanism of
scale formation.
The new designed heat exchanger experimental system was used after carrying out the basic process designs of the
system. This system was used to study the effect of the temperature (40-90 °C) and water flow rate (0.6-1.2 L/min) on
the total hardness with time as a function of precipitation of hardness salts from water and scale formation.
Different magnetic field designs in the heat exchanger experimental system were used to study the effect of magnetic
field design a

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Publication Date
Wed Mar 30 2022
Journal Name
Iraqi Journal Of Science
Retrieval of Timewise Coefficients in the Heat Equation from Nonlocal Overdetermination Conditions
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     This paper investigates the simultaneous recovery for two time-dependent coefficients for heat equation under Neumann boundary condition. This problem is considered under extra conditions of nonlocal type. The main issue with this problem is the solution unstable to small contamination of noise in the input data. The Crank-Nicolson finite difference method is utilized to solve the direct problem whilst the inverse problem is viewed as nonlinear optimization problem. The later problem is solved numerically using optimization toolbox from MATLAB. We found that the numerical results are accurate and stable.

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
comparison between the methods estimate nonparametric and semiparametric transfer function model in time series the Using simulation
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 The transfer function model the basic concepts in the time series. This model is used in the case of multivariate time series. As for the design of this model, it depends on the available data in the time series and other information in the series so when the representation of the transfer function model depends on the representation of the data In this research, the transfer function has been estimated using the style nonparametric represented in two method  local linear regression and cubic smoothing spline method The method of semi-parametric represented use semiparametric single index model, With four proposals, , That the goal of this research is comparing the capabilities of the above mentioned m

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Publication Date
Mon Jun 01 2009
Journal Name
Al-khwarizmi Engineering Journal
Effect of Adding Alcohols and Gas Velocity on Gas Hold up and Mass Transfer Coefficient in Bubble Columns with Draught Tube
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     The bubble columns are widely used as a two or three phase reactor in industrial chemical process such as absorption, biochemical reactions, coal liquefaction, etc. To design such a column, two main parameters should be taken in consideration, the gas hold-up (), and the liquid phase mass transfer coefficient KLa. The study includes the effect of gas velocity and the addition of alcohols on gas hold-up and mass transfer coefficient in bubble column with draught tube when the length of the column is 1.5m and the ratio of the draught tube diameter to the column diameter equals 0.5 and the air dispersion into the base of the draught tube using a multi hole tuyere is equivalent to a diameter of 0.15 mm and

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Publication Date
Fri Jan 10 2025
Journal Name
Al-khwarizmi Engineering Journal
Numerical Analysis of Double Diffusive Laminar Natural Convection in a Right Angle Triangular Solar Collector
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Publication Date
Fri Nov 24 2023
Journal Name
Iraqi Journal Of Science
Assessment natural radioactivity of marl as raw material at Kufa Cement Quarry in Najaf Governorate
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This Research involves radiological study to assess the marl layer in the Euphrates Formation (Early Miocene) as a raw material for Portland cement industry. Nine wells are drilled penetrating the marl layer to the limestone beneath it. Nine samples were collected from core wells. Each sample represents one well. The concentration of the natural radionuclides 226Ra, 232Th and 40K are 14.91, 5.16 and 223.98 Bq/kg-1, respectively. They are determined by using the technique of gamma-ray spectroscopy with HPGe detector. The radiation doesn't exceed the globally
permissible limits. Then the results were compared with the reported data of other countries and with the world average activity of cement raw materials. The radium equivalent (Rae

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