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Modelling of electron trajectories inside SEM chamber concerning mirror effect phenomenon
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A computational investigation is carried out to describe the behaviour of reflected electrons upon a charged insulator sample and producing mirror effect images. A theoretical expression for the scanning electron path equation is derived concerning Rutherford scattering and some electrostatic aspects. The importance of the derived formula come from its correlation among some of the most important parameters that controls the mirror effect phenomena. These parameters, in fact, are the trapped charges, incident angle and the scanning potential which investigated by considering its influences on the incident electrons. A pervious experimental operation requirements are adopted for operating the introduced expression. However, the obtained results are almost encouraged for using the presented expression to simulate the electron trajectory in sense of mirror effect.

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Publication Date
Fri Jun 29 2018
Journal Name
Journal Of Engineering
Numerical Investigation of the Effect of Inserted Twisted Tape inside Submerged Bundle Tubes on its Thermal Performance
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Twisted tape insertion in the smooth plain tube is one of the types of passive methods that are used to enhance heat transfer. Swirl fluid flow inside the tube and related heat transfer characteristics are very complex. ANSYS FLUENT (V 16.1) and ASPEN industrial program are used in analyzing this technique for enhancement heat transfer. A circular plain tube has length L=8534mm and 17 mm inner diameter with a twisted tape of twist ratio of y = (H/D) = (150/17) =8.8 along the plain tube were considered for this study. Eight Reynolds numbers (Re) of 784, 1000, 2000, 3000, 4000, 5000, 6000 and 7000 are used to analyze the response of thermal performance. Crude oil API 28 exit temperature, film heat transfer coefficient, Nus

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Publication Date
Sat Dec 30 2023
Journal Name
Iraqi Journal Of Science
Designing Cassegrain Telescope System with Best Obscuration Ratio of Secondary Mirror
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     A computer simulation was conducted using Optics Software for Layout and Optimization (OSLO) to design a Cassegrain telescope system for on-axis rays. In order to establish such a telescope, the two mirrors of the optical system were designed as spherical surfaces: a concave mirror and a convex mirror. The obscuration ratios of the Cassegrain telescope's secondary mirror were examined using different values, which ranged between 0.1 and 0.3, to determine the best obscuration ratio. This work adopted three criteria to decide which obscuration ratio is the best for the Cassegrain telescope. The first criterion was the number of rays that reached the final image. The second criterion was calculating the modulation transfer function

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Publication Date
Sat Apr 01 2023
Journal Name
Physics Of Atomic Nuclei
Differences in Ground State Properties of Some Mirror Nuclei
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Publication Date
Tue Sep 30 2008
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
COMPUTATIONAL ANALYSIS OF THE MIXING ZONE IN THE COMBUSTION CHAMBER OF RAMJET
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A theoretical analysis of mixing in the secondary combustion chamber of ramjet is presented. Theoretical investigations were initiated to insight into the flow field of the mixing zone of the ramjet combustor and a computer program to calculate axisymmetric, reacting and inert flow was developed. The mathematical model of the mixing zone of ramjet comprises differential equations for: continuity, momentum, stagnation enthalpy, concentration, turbulence energy and its dissipation rate. The simultaneous solution of these equations by means of a finite-difference solution algorithm yields the values of the variable at all internal grid nodes.
The results showed that increasing air mass flow (0.32 to 0.64 kg/s) increases the development o

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Publication Date
Tue Nov 01 2016
Journal Name
Journal Of Engineering
Automatically Maintain Climatic Conditions inside Agricultural Greenhouses
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In this work, a novel system is designed to remote monitor / automatic control of the temperature, humidity and soil moisture of the agricultural greenhouses. In the proposed system, the author used the mentioned sensors for monitoring the climatic conditions of the agricultural greenhouses; and the system makes a controlling process to fix the required parameters for plant growth by running / stopping the fan, air exchanger and irrigation devices when any changes happened in these parameters. The presented system is based on XBee protocol in the implemented wireless sensor star topology network (WSN) to monitor the agricultural greenhouses in real time, and used the GSM and Internet technologies to monitor the agricultu

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Publication Date
Wed Nov 30 2022
Journal Name
Iraqi Journal Of Science
Dosimetric Verification of Grid Radiotherapy Using Three Ionization Chamber Detectors o Dosimetry
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     This study aims to provide verification between measured and calculated radiation dose using three different ionization chamber detectors in Grid plans to select the best ones To the best of our knowledge, this is the first practical experiment in such subject. Grid radiotherapy is an unconventional method for bulky tumors treatment. It is characterized by a single-fraction and high radiation dose. Ten cases (scenarios) were selected to achieve Grid plans by MLCs, with a single dose of 1500-2000 cGy. Three ionization detectors were employed to measure the maximum, mean, and point doses (cGy), and match them with those calculated by the linear accelerator used in this study. The results showed significant differences among the th

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Publication Date
Sat Feb 20 2010
Journal Name
Indian Journal Of Science And Technology
Investigation on picosecond laser ablation of dental material using FIB/SEM techniques
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Publication Date
Wed Apr 19 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Design for Two Electrodes Electrostatic Mirror by using the Bimurzaev Technique
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This paper describes theoretical modeling of electrostatic mirror based on two cylindrical electrodes, A computational investigation has been carried out on the design and properties of the electrostatic  mirror. we suggest a mathematical expression to represent the axial potential of an electrostatic mirror. The  beam path  by using the Bimurzaev technique have been investigated as a mirror trajectory with the aid of Runge – Kutta  method. the electrode shape of mirror two electrode has been determined by using package SIMION computer program . The spherical and chromatic aberrations coefficients of mirror has been computed and normalized in terms of the focal length. The choice of the mirror depends on the op

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Publication Date
Thu Apr 27 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Space Charge Effect for Design Electron Gun Using Five Electrode Immersion Electrostatic Lenses
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 Computer theoretical study has been carried out on the design of five electrode immersion electrostatic lens used in electron gun application. The finite element method (FEM) is used in the solution of the Poisson's equation fro determine axial potential distribution, the electron trajectory under Zero magnification condition .      The optical  properties : focal length ,spherical and chromatic aberrations are calculated,From studying the properties of the designed electron gun. we have good futures for these  electron gun where are abeam current 4*10-4A    can be supplied by using cathode tip of radius 100 nm.

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Publication Date
Tue May 30 2023
Journal Name
Iraqi Journal Of Science
Mathematical Modelling for Peristaltic Flow of Sutterby Fluid Through Tube under the Effect of Endoscope
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     In this work, the mathematical modelling of peristaltic transport for incompressible Sutterby fluid through the cavity between coaxial tubes where the inner tube is fixed and the outer tube has sinusoidal rhythmic fluctuations along the channel’s walls is presented. Under the assumption of long wavelength and the low Reynolds number, the governing equations (motion, temperature, and concentration) are illustrated in cylindrical coordinates. The analytical solution for the temperature and concentration of the fluid flow is obtained using Mathematica 11.3, whereas the perturbation technique is employed to find the closed form of the velocity profile. The variation of the axial velocity, stream function, temperat

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