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jih-2798
Birefringence for Elliptical-Core Fibers with Low Ellipticities
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Model birefringence was measured for elliptical-core fibers with low ellipticities, note the birefringence depends strongly on the frequency, especially when fiber is being operated near the higher mode cutoff where ν  for circular fiber of the single-mode type that correspond to the birefringence maximum. When ν  this also correspond to the birefringence maximum that can be introduced in an elliptical core fiber while still operating in the single-mode regime near the higher mode cutoff. Also the birefringence is proportional to the fiber core ellipticity when core ellipticity is much less than unity, but this birefringence deviates from the linear for the large core ellipticities.

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Publication Date
Sun Mar 07 2010
Journal Name
Baghdad Science Journal
Low Loss in a Gas Filled Hollow Core Photonic crystal fiber
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The work in this paper focuses on the experimental confirming of the losses in photonic crystal fibers (PCF) on the transmission of Q-switched Nd:YAG laser. First HC-PCF was evacuated to 0.1 mbar then the microstructure fiber (PCF) was filled with He gas & gas. Second the input power and output power of Q-switched Nd:YAG laser was measured in hollow core photonic bandgap fiber (HCPCF). In this work loss was calculated in the hollow core photonic crystal fiber (HCPCF) filled with air then N2, and He gases respectively. It has bean observed that the minimum loss obtained in case of filling (HC-PCF) with He gas and its equal to 15.070 dB/km at operating wavelength (1040-1090) nm.

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Publication Date
Tue Oct 01 2019
Journal Name
Journal Of Engineering
Generation and Experimental Stress Analysis of Elliptical Gears with Combined Teeth
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In this study, generation of elliptical gears with different teeth profiles of crowned involute, double circular arc (DCA), and combined (crowned involute with DCA) has been developed. The resulting mathematical equations have been computerized and feed to CNC end mill machine to manufacture elliptical gear models with different profiles. These models are investigated in plane polariscope to show the resulting stresses under certain load. Comparison of photo-elastic stress results shows that combined elliptical gears with DCA side as a loaded side have a minimum resulting contact stress with a reduction percentage of 40% compare with contact stresses in counterpart elliptical gear of involute profile (which is commonly u

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Publication Date
Sun Aug 13 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Studying Of Image Intensity Distribution Of Elliptical Object (Elliptical Spread Function)
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      In this work, a new formula of intensity distribution in image plane of elliptical object was founded (Elliptical spread function), by using optical system including circular aperture. The Gauss quadrature method of numerical integral was used for calculating equation's integrals. Curves are shown for system having focal error and intensity distribution in focal axis.  

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Publication Date
Sat Mar 01 2008
Journal Name
Iraqi Journal Of Physics
Transverse Magnetic Form Factor for 13C(e,e) 13C with Core-Polarization Effects
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Elastic magnetic M1 electron scattering form factor has been calculated for the ground state J,T=1/2-,1/2 of 13C. The single-particle model is used with harmonic oscillator wave function. The core-polarization effects are calculated in the first-order perturbation theory including excitations up to 5ħω, using the modified surface delta interaction (MSDI) as a residual interaction. No parameters are introduced in this work. The data are reasonably explained up to q~2.5fm-1 .

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Publication Date
Thu Oct 20 2022
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Calculation of Modes Properties for Single-Mode and Multimode Fibers at 633 nm
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The need for optical fibers has emerged for its ability to transmit information with less attenuation and over long distances. In this work, four optical fibers with core radii from 1 μm to 4.75 μm in steps of 1.25 μm and a numerical aperture of 0.17 were studied and their modes properties have been calculated at a wavelength of 633 nm by using RP Fiber Calculator (free version 2022). Also, the effect of increasing the core radius on these properties has been studied. Multimode fibers can be obtained when the radius of the fiber core is large compared to the operating wavelength of the fiber which is less than the cutoff wavelength of the mode. Otherwise, a single-mode fiber is obtained. It has been concluded that all the calculated p

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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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Publication Date
Fri Jul 26 2019
Journal Name
Dental Materials Journal
Semi-interpenetrating network composites reinforced with Kevlar fibers for dental post fabrication
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Publication Date
Fri Jan 26 2024
Journal Name
Iraqi Journal Of Science
Longitudinal and Transverse Electron Scattering Form Factors for 13C Nucleus with Core-Polarization Effects
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Inelastic electron scattering have been studied for (3.68 )
2
1
2
3
MeV

,
(7.55 )
2
1
2
5
MeV

(15.11 )
2
3
2
3
MeV

states in the 13C nucleus. 4He is considered as an inert core with
nine nucleons out of it (the model space of nucleus). Form factors are calculated by
using Cohen-Kurath interaction for 1p-shell model space with Modified Surface
Delta Interaction (MSDI) as a residual interaction for higher configuration. The
study of core-polarization effects on the form factors is based on microscopic
theory, which combines shell model wave functions and configurations with higher
energy as the first order perturbation. The radial wave functions

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Publication Date
Mon Oct 28 2019
Journal Name
Iraqi Journal Of Science
Re-Evaluation Solution Methods for Kepler's Equation of an Elliptical Orbit
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An evaluation was achieved by designing a matlab program to solve Kepler’s equation of an elliptical orbit for methods (Newton-Raphson, Danby, Halley and Mikkola). This involves calculating the Eccentric anomaly (E) from mean anomaly (M=0°-360°) for each step and for different values of eccentricities (e=0.1, 0.3, 0.5, 0.7 and 0.9). The results of E were demonstrated that Newton’s- Raphson Danby’s, Halley’s can be used for e between (0-1). Mikkola’s method can be used for e between (0-0.6).The term  that added to Danby’s method to obtain the solution of Kepler’s equation is not influence too much on the value of E. The most appropriate initial Gauss value was also determined to

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Publication Date
Sun Oct 01 2017
Journal Name
Journal Of Mechanical Science And Technology
Optimization of a rectangular pin fin using elliptical perforations with different inclination angles
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