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Nonlinear Optical Properties of PMMA Composites Using Z-Scan Technique
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The nonlinear refractive index and the nonlinear absorption coefficient of unmodified and functional poly(methyl methacrylate) PMMA films were studied before and after the addition of the filler by the z-scan technique, using a Q-switched Nd:YAG laser at two wavelengths: 532 nm and 1064 nm, and at three input energies (13, 33 and 53) mJ. Both linear and nonlinear refractive indices and absorption coefficients of polymer films were studied by using UV-VIS spectrophotometer. The results show that the creation of functional PMMA from unmodified PMMA will increase the nonlinear optical properties in the functional PMMA/copper matrix more than in the unmodified PMMA/copper matrix. Hence, the functional PMMA appears promising as a useful third-order nonlinear material. The nonlinear refractive index is directly proportional to the input intensity and directly proportional to the increase in the concentration of the filler, while the nonlinear absorption coefficient is inversely proportional to the input energy and inversely proportional to the increase in the concentration of the filler. The nonlinear effect is more enhanced at the 532 nm wavelength than at 1064 nm..

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Publication Date
Wed Jun 01 2022
Journal Name
Results In Engineering
Behavioral nonlinear modeling of prestressed concrete flexural members with internally unbonded steel strands
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Publication Date
Fri Mar 01 2019
Journal Name
Spatial Statistics
Efficient Bayesian modeling of large lattice data using spectral properties of Laplacian matrix
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Spatial data observed on a group of areal units is common in scientific applications. The usual hierarchical approach for modeling this kind of dataset is to introduce a spatial random effect with an autoregressive prior. However, the usual Markov chain Monte Carlo scheme for this hierarchical framework requires the spatial effects to be sampled from their full conditional posteriors one-by-one resulting in poor mixing. More importantly, it makes the model computationally inefficient for datasets with large number of units. In this article, we propose a Bayesian approach that uses the spectral structure of the adjacency to construct a low-rank expansion for modeling spatial dependence. We propose a pair of computationally efficient estimati

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Publication Date
Tue Jan 01 2019
Journal Name
Technologies And Materials For Renewable Energy, Environment And Sustainability: Tmrees19gr
Improvement of some mechanical properties of epoxy using uncarbonized and carbonized eggshell powder
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Publication Date
Wed Feb 29 2012
Journal Name
Al-khwarizmi Engineering Journal
Effect of Solid Properties on Axial Liquid Dispersion in Bubble Column
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Experiments were conducted to study axial liquid dispersion coefficient in slurry bubble column of 0.15 m inside diameter and 1.6 m height using perforated plate gas distributor of 54 holes of a size equal to 1 mm diameter and with a 0.24 free area of holes to the cross sectional area of the column. The three phase system consists of air, water and PVC used as the solid phase. The effect of solid loading (0, 30 and 60 kg/m3) and solid diameter (0.7, 1.5 and 3 mm) on the axial liquid dispersion coefficient at different axial location (25, 50 and 75 cm) and superficial gas velocity covered homogeneous-heterogeneous flow regime (1-10 cm/s) were studied in the present work. The results show that the axial liquid dispersion coeffic

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Publication Date
Tue Jan 08 2019
Journal Name
Arab Science Heritage Journal
الأمير كوركوز الاويغوري دراسة في سيرته ودوره السياسي والاداري والاقتصادي والعمراني خلال العصر العباسي 624-641 هـ/ 1226- 1243 م
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حظيت عدد من الشخصيات التاريخية ممن كان لها أثر واضح المعالم في تطور النظام الإداري والسياسي للإمبراطورية المغولية، بأهتمام عدد لا بأس به من الباحثين.

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Publication Date
Wed Jan 01 2025
Journal Name
Aip Conference Proceedings
Optical information verification and authentication: Exploring sparsity constraints and optical encryption for enhanced security
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Publication Date
Fri Jul 21 2023
Journal Name
Journal Of Engineering
Water Flow Visualization And Velocity Measurement Using Hydrogen Bubble Generation Technique In Low Speed Open Channel
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Visualization of water flow around different bluff bodies at different Reynolds number ranging (1505 - 2492) was realized by designing and building a test rig which contains an open channel capable to ensure water velocity range (4-8cm/s) in this channel. Hydrogen bubbles generated from the ionized water using DC power supply are visualized by a light source and photographed by a digital camera. Flow pattern around a circular disk of (3.6cm) diameter and (3mm) thickness, a sphere of (3.8cm) diameter and a cylinder of
(3.2cm) diameter and (10cm) length are studied qualitatively. Parameters of the vortex ring generated in the wake region of the disk and the separation angle of water stream lines from the surface of the sphere are plott

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Publication Date
Mon Dec 31 2018
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
EFFECT OF PLASTIC WASTES AS LOW COST MATERIAL ON SOME PROPERTIES OF UNSATURATED POLYESTER.: EFFECT OF PLASTIC WASTES AS LOW COST MATERIAL ON SOME PROPERTIES OF UNSATURATED POLYESTER.
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In this study, plastic wastes named (PET and PVC) were used to prepare polymer matrix composite (PMC) which can be used in different applications. Composite materials were prepared by mixing unsaturated polyester resin (UP) with plastic wastes, two types of plastic waste were used in this work included polyethylene-terephthalate (PET) and Polyvinyl chloride (PVC) with various weight fractions (0, 5,10,15, 20 and 25%) added as a filler in flakes form. In this work, some of the tests that were carried out included (tensile, bending, and compressive strength) as mechanical tests, in addition to (thermal conductivity and water absorption) as physical tests. The values of tensile, compressive strength and Young's modulus of UP increased after

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Publication Date
Mon Jun 08 2026
Journal Name
Al-rafidain University College For Sciences
“Simple Regression Analysis by using Linear Programming Technique and illustration of Absolute Residuals method with another Estimation Techniques”
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This research deals with unusual approach for analyzing the Simple Linear Regression via Linear Programming by Two - phase method, which is known in Operations Research: “O.R.”. The estimation here is found by solving optimization problem when adding artificial variables: Ri. Another method to analyze the Simple Linear Regression is introduced in this research, where the conditional Median of (y) was taken under consideration by minimizing the Sum of Absolute Residuals instead of finding the conditional Mean of (y) which depends on minimizing the Sum of Squared Residuals, that is called: “Median Regression”. Also, an Iterative Reweighted Least Squared based on the Absolute Residuals as weights is performed here as another method to

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Publication Date
Thu Sep 01 2016
Journal Name
Arabian Journal Of Geosciences
Assessment of interconnection between surface water and groundwater in Sawa Lake area, southern Iraq, using stable isotope technique
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