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Comparison the Physical and Mechanical Properties of Composite Materials (Al /SiC and Al/ B4C) Produced by Powder Technology
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In this investigation, metal matrix composites (MMCs) were manufactured by using powder technology. Aluminum 6061 is reinforced with two different ceramics particles (SiC and B4C) with different volume fractions as (3, 6, 9 and 12 wt. %). The most important applications of particulate reinforcement of aluminum matrix are: Pistons, Connecting rods etc. The specimens were prepared by using aluminum powder with 150 µm in particle size and SiC, B4C powder with 200 µm in particle size. The chosen powders were mixed by using planetary mixing setup at 250 rpm for 4hr.with zinc stearate as an activator material in steel ball milling. After mixing process the powders were compacted by hydraulic unidirectional press type (Leybold Harris No. 36110) at 250 Kg/cm2 according to (ASTM-D 618). Finally the green compacts were sintered at 500  for 3 hr. by using electrical furnace with argon atmosphere. There are many examinations and tests were done for the produced metal matrix composites (MMCS), (Al/ SiC and Al/B4C) such as examination of the microstructure, mechanical tests (hardness and compressive strength), physical tests (density test before and after sintering, also porosity test). The results of this investigation showed that improving the physical properties (theoretical density, experimental density, porosity) and mechanical properties (Rockwell hardness and compressive strength).

 

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Publication Date
Fri Feb 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of Some Methods for Estimating the Scheff'e Model of the Mixture
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Because of the experience of the mixture problem of high correlation and the existence of linear MultiCollinearity between the explanatory variables, because of the constraint of the unit and the interactions between them in the model, which increases the existence of links between the explanatory variables and this is illustrated by the variance inflation vector (VIF), L-Pseudo component to reduce the bond between the components of the mixture.

    To estimate the parameters of the mixture model, we used in our research the use of methods that increase bias and reduce variance, such as the Ridge Regression Method and the Least Absolute Shrinkage and Selection Operator (LASSO) method a

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Publication Date
Sat Apr 20 2024
Journal Name
International Journal Of Disabilities Sports & Health Sciences
Psychological Toughness and its Relationship to Some Coordination, Physical Abilities and Accuracy of Some Basic Skills Performance Among the Iraqi Junior National Handball Team Players
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The aim of the research is to identify psychological toughness and its relationship to some coordination, physical abilities and accuracy of some basic performance skills among the players of the Iraqi junior national handball team players. The hypothesis is the existence of a correlation between psychological toughness, coordination, physical abilities, and the accuracy of some basic skills performance among the players of the Iraqi junior national handball team players. The descriptive approach in the style of correlational relations used to suit the research problem, as the community was determined by (18) players for the Iraqi junior national handball team players, while the sample was (14) players, and the samp

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Publication Date
Wed Jun 29 2022
Journal Name
Journal Of The College Of Education For Women
The Reality of Teachers’ Use of Modern Technologies in Teaching Arabic as a Second Language in Terms of Objectives and Selection Foundations at the Institute of Arabic Language in Umm Al-qura University Mamoun Eltigani Hassan Eldali
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This study aims to know the degree of importance and the availability of the enhancing specifications of the educational process, and the way its objectives are achieved. Such a step involves using educational techniques, laying the selection foundations, knowing the methods of their employment and tracking the obstacles that limit this employment in teaching Arabic to non-native speakers. To achieve these objectives, the study followed a descriptive approach, and collected the necessary data through an integrated questionnaire prepared for the purpose of describing the phenomenon or topic. This approach was adopted, as it is characterized by being comprehensive, focuses on collecting data related and necessary to the topic under study.

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Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Clinical And Experimental Dentistry
Comparison of the accuracy of intraoral digital impression system and conventional impression techniques for multiple implants in the full-arch edentulous mandible
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Publication Date
Sat Dec 28 2024
Journal Name
Journal Of College Of Physical Education
Design and standardization of a progressively difficult educational test for football passing skills for first-year students in the College of Physical Education and Sports Sciences
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Standards play a vital role in documenting the values ​​of new test results in the form of tables. They are one of the basic requirements that the standardization process aims for as a complement to standardizing test procedures, and contribute to knowing the current reality of the student. The degree of readiness and level as a result of practicing different exercises for sports activities, in addition to the possibility of adopting it for comparison with his group or similar groups, classification, prediction and selection. Developing the skill of handling the football in the educational field is an important matter for achieving distinguished performance among students. This skill requires a level of accuracy, speed and control, and

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Publication Date
Wed Dec 01 2021
Journal Name
Baghdad Science Journal
Boubaker Wavelets Functions: Properties and Applications
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This paper is concerned with introducing an explicit expression for orthogonal Boubaker polynomial functions with some important properties. Taking advantage of the interesting properties of Boubaker polynomials, the definition of Boubaker wavelets on interval [0,1) is achieved. These basic functions are orthonormal and have compact support. Wavelets have many advantages and applications in the theoretical and applied fields, and they are applied with the orthogonal polynomials to propose a new method for treating several problems in sciences, and engineering that is wavelet method, which is computationally more attractive in the various fields. A novel property of Boubaker wavelet function derivative in terms of Boubaker wavelet themsel

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Publication Date
Tue Nov 01 2016
Journal Name
Renewable And Sustainable Energy Reviews
Dye-sensitised solar cells: Development, structure, operation principles, electron kinetics, characterisation, synthesis materials and natural photosensitisers
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Publication Date
Wed Feb 20 2019
Journal Name
Iraqi Journal Of Physics
A comparison between PCA and some enhancement filters for denoising astronomical images
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This paper includes a comparison between denoising techniques by using statistical approach, principal component analysis with local pixel grouping (PCA-LPG), this procedure is iterated second time to further improve the denoising performance, and other enhancement filters were used. Like adaptive Wiener low pass-filter to a grayscale image that has been degraded by constant power additive noise, based on statistics estimated from a local neighborhood of each pixel. Performs Median filter of the input noisy image, each output pixel contains the Median value in the M-by-N neighborhood around the corresponding pixel in the input image, Gaussian low pass-filter and Order-statistic filter also be used.

Experimental results shows LPG-

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Publication Date
Tue Mar 24 2009
Journal Name
Proceeding Of 3rd Scientific Conference Of The College Of Science, University Of Baghdad.
A Comparison Between Galactic and Large Magellanic Cloud (LMC) Interstellar Extinction Curves
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Average interstellar extinction curves for Galaxy and Large Magellanic Cloud (LMC) over the range of wavelengths (1100 A0 – 3200 A0) were obtained from observations via IUE satellite. The two extinctions of our galaxy and LMC are normalized to Av=0 and E (B-V)=1, to meat standard criteria. It is found that the differences between the two extinction curves appeared obviously at the middle and far ultraviolet regions due to the presence of different populations of small grains, which have very little contribution at longer wavelengths. Using new IUE-Reduction techniques lead to more accurate result.

Publication Date
Tue Jan 01 2013
Journal Name
Iraqi Journal Of Physics
A comparison between PCA and some enhancement filters for denoising astronomical images
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This paper includes a comparison between denoising techniques by using statistical approach, principal component analysis with local pixel grouping (PCA-LPG), this procedure is iterated second time to further improve the denoising performance, and other enhancement filters were used. Like adaptive Wiener low pass-filter to a grayscale image that has been degraded by constant power additive noise, based on statistics estimated from a local neighborhood of each pixel. Performs Median filter of the input noisy image, each output pixel contains the Median value in the M-by-N neighborhood around the corresponding pixel in the input image, Gaussian low pass-filter and Order-statistic filter also be used. Experimental results shows LPG-PCA method

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