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Stress Concentration factor Analysis of Helical Gear Drives with Asymmetric Teeth Profiles
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This study investigates the influence of asymmetric involute teeth profiles for helical gears on the bending stress. Theoretically, bending stress has been estimated in spur involute gears which have symmetric teeth profile by based on the Lewis, 1892 equation. Later, this equation is developed by, Abdullah, 2012. to determine the effect of an asymmetric tooth profile for the spur gear on the bending stress. And then these equations are applied with stress concentration factor once for symmetric and once other for asymmetric teeth profile. In this paper, the bending stresses for various types of helical gear with various types of asymmetric teeth profile are calculated numerically for defined the stress concentration factor. The numerical solution based on the finite element method technique which that done by using the software simulation SolidWorks 2016. The results of this study indicate that the helical gear drive with asymmetric teeth profile having 'loaded side pressure angle' of ( ) and 'unloaded side pressure angle' of ( ) is better than a helical gear with standard teeth profile having pressure angle of ( ) from the regarding of tooth bending strength. Also, notes that the great enhancement in the results of maximum tooth bending stress for modified involute of tooth profile compared with the standard teeth profile. In addition to, predict the equation of stress concentration factor which is a function of both unloaded side pressure angle and helix angle and then it used with Abdullah equation for to determine the nominal stresses in the root fillet.

 

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Publication Date
Mon Mar 11 2019
Journal Name
Baghdad Science Journal
Effects of Discharge Current and Target Thickness in Dc-Magnetron Sputtering on Grain Size of Copper Deposited Samples
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A study of the effects of the discharge (sputtering) currents (60-75 mA) and the thickness of copper target (0.037, 0.055 and 0.085 mm) on the prepared samples was performed. These samples were deposited with pure copper on a glass substrate using dc magnetron sputtering with a magnetic flux density of 150 gauss at the center. The effects of these two parameters were studied on the height, diameter, and size of the deposition copper grains as well as the roughness of surface samples using atomic force microscopy (AFM).The results of this study showed that it is possible to control the specifications of copper grains by changing the discharge currents and the thickness of the target material. The increase in discharge curre

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Publication Date
Sat Dec 15 2018
Journal Name
Journal Of Baghdad College Of Dentistry
Comparative evaluation of the radiographic density of GuttaFlow® 2 in different obturation techniques using Spiral Computed Tomography
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Background: Ideal root canal obturation depends on many factors; one of them is good sealing of root canal without pores. The aim of this study was to determine the radiographic density of GuttaFlow® 2 with different obturation techniques using spiral computed tomography. Materials and Methods: Forty palatal roots of permanent maxillary first molar were used in this study. Following working length determination, root canal was prepared using rotary PROTAPER universal system. They were randomly divided into four groups of 10 roots each, the groups are Conventional lateral condensation with Apexit Plus sealer, Conventional lateral condensation with GuttaFlow® 2 as a sealer, Soft Core Regular with GuttaFlow® 2 as a sealer and singl

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Publication Date
Sun Dec 01 2013
Journal Name
Journal
The Effects Of Pbl On Understanding Of Thermodynamics, Group Work And Self-Directed Learning Skills Among Physics Undergraduates
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The aim of this study is to compare the effects of three methods: problem-based learning (PBL), PBL with lecture method, and conventional teaching on the understanding of thermodynamics, group work and self-directed learning skills among physics undergraduates. The actual sample size comprises of 122 students, who were selected randomly from the Physics Department, College of Education in Iraq, for academic year 2011-2012. In this study, the pre and posttest were done and the instruments were administered to the students for data collection. Inferential statistics were employed to analyze data. The independent variables were the PBL, the PBL with lecture method, and the conventional teaching. Dependent variables of statistical analysis were

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Publication Date
Fri Apr 01 2022
Journal Name
Chemical Engineering Science
Numerical modelling of flow through nodes in foams within the “dry” limit in the presence of solid particles
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Publication Date
Sun Jan 01 2017
Journal Name
Aes-atema International Conference Series - Advances And Trends In Engineering Materials And Their Applications
Behavior of back filler friction spot welded joints of similar AA2024-T3 & AA6061-T6 aluminum alloy sheets
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Publication Date
Tue Jun 15 2021
Journal Name
Al-academy
The Relations Of Design And The Role Of It Making The Idea For Fashion Design: فرات جمال العتابي
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Any design subject to a set of forces contributing to the establishment of relations working to strengthen the internal elements of the design; any imbalance in these elements can make a fragmented and weak design, thus preventing it from achieving the goal or performance. Poor performance can be attributed to various factors: the extent and function of the elements and principles in the design, realization of the idea, especially in fashion design.
Moreover, there are many aspects of a design that go into achieving the realization of the designer’s idea. The design utilizes a lot of stimulants by drawing attention to its design, which is consistent with the need for psychological and material individuals. In this research, we will

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Publication Date
Wed Jan 02 2019
Journal Name
Journal Of Educational And Psychological Researches
The Vision and Reality of Quality Standards in College Of Education / Ibn Al-Haytham from university teachers' perspective
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The problem of research is that the colleges of education in general and the College of Education in particular continue to follow traditional administrative patterns and that there is a complaint that the educational outputs do not match the aspirations of the society and its future directions. The aim of the research is to identify the reality of quality assurance standards in the college and to create a future vision for these standards to apply them. The researcher has designed a questionnaire based on the responses of the research sample which consisted of a group of university teachers to identify the quality assurance standards. The findings revealed that it is necessary to find a clear approach to apply the standards of quality i

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Publication Date
Wed Jun 15 2022
Journal Name
Malaysian Journal Of Science
STUDY THE RELATIONSHIP BETWEEN BREMSSTRAHLUNG DOSE RATE AND THE ENERGY OF BETA RAY FOR DIFFERENT TYPES OF SHIELD
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The dose rate for bremsstrahlung radiation from beta particles with energy (1.710) MeV and (2.28) MeV which comes from (32P and 90Y) beta source respectively have been calculated through six materials (polyethylene, wood, aluminum, iron, tungsten and lead) for first shielding material with thickness (x=1) mm which are putting between beta sources and second shield (polyethylene, aluminum and lead) with thickness (1, 2 &4) mm have been calculated. The distance between beta source and second shield is constant (D=1) cm. This dose rate was found by program called Rad Pro Calculator (version 3.26). The results of dose rate of beta particles were plotted as a function to the atomic number (Z) for first shield materials for each

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Publication Date
Mon Apr 03 2023
Journal Name
Journal Of Educational And Psychological Researches
The Effectiveness of a Developed Unit in The Arabic Language Textbook for The Enhancement of 21st Century Skills
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Abstract

This research aims to develop a unit as part of a sixth-grade Arabic language textbook and measure its effectiveness in the development of twenty-first-century skills of female students. The author adopted the experimental approach with a quasi-experimental design of the pre-post single-group. A list of the major skills was derived from the framework for the 21st-century skills of the mother tongue that was developed by the Partnership for 21st-Century Skills and reviewed and adjusted by some specialists. According to their views, the unit was developed. The study targeted 15 sub-skills falling under three main skills. The results of the study showed the effectiveness of the developed unit in the develo

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Publication Date
Tue Jun 01 2021
Journal Name
Al-anbar Medical Journal
Evaluation of Antimicrobial Activity of Plants Extract Against Bacterial Pathogens Isolated from Urinary Tract Infection among Males Patients
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Urinary tract infection (UTI) is a considerable problem aecting the health of people each year. It is caused by various Gram-positive (G+ve) and Gram-negative (G-ve) pathogens. It is an important illness in the world aecting all age groups across their life span. Objectives: To identify the most common aerobic bacteria that cause UTIs and their antibiotic susceptibility and antimicrobial activity of plant extracts of the males' patients. Materials and methods: The study involved 35 midstream urine samples from the male students (University of Baghdad, Baghdad, Iraq) with suspicious symptoms of UTI, during the period from January-March 2018. Each urine sample was cultured rst on Mannitol Salt Agar and MacConkey agar plates to dierentiate

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