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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
Wed Oct 24 2018
Journal Name
Chemistry Of Materials
Oxidant or Catalyst for Oxidation? A Study of How Structure and Disorder Change the Selectivity for Direct versus Catalytic Oxidation Mediated by Manganese(III,IV) Oxides
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Structure type and disorder have become important questions in catalyst design, with the most active catalysts often noted to be “disordered” or “amorphous” in nature. To quantify the effects of disorder and structure type systematically, a test set of manganese(III,IV) oxides was developed and their reactivity as oxidants and catalysts tested against three substrates: methylene blue, hydrogen peroxide, and water. We find that disorder destabilizes the materialsthermodynamically, making them stronger chemical oxidantsbut not necessarily better catalysts. For the disproportionation of H2O2 and the oxidative decomposition of methylene blue, MnOx-mediated direct oxidation competes with catalytically mediated oxidation, making the most

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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
Thu Dec 01 2011
Journal Name
Journal Of Engineering
ESTIMATION THE 7 AND 28- DAY NORMAL COMPRESSIVE STRENGTH BY ACCELERATED TEST METHODS IN CONCRETE
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Curing of concrete is the maintenance of a satisfactory moisture content and temperature for a
period of time immediately following placing so the desired properties are developed. Accelerated
curing is advantages where early strength gain in concrete is important. The expose of concrete
specimens to the accelerated curing conditions which permit the specimens to develop a significant
portion of their ultimate strength within a period of time (1-2 days), depends on the method of the
curing cycle.Three accelerated curing test methods are adopted in this study. These are warm water,
autogenous and proposed test methods. The results of this study has shown good correlation
between the accelerated strength especially for

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Publication Date
Wed Dec 15 2021
Journal Name
Arab World English Journal
Reading Difficulties in English as a Second Language in Grade Five at a Saint Patrick’s High School for Boys, Hyderabad- India
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Reading is one of the essential components of the English language. Countries that use English as a second language (ESL) sometimes have difficulties in reading and comprehension. According to many researches, mother tongue has proved some interferences with learning a second language. This study investigated the results of reading difficulties of young second language learners in terms of accuracy, comprehension, and rate using the Neale Analysis of Reading Ability test. The study was carried out in one of the High Schools for Boys in Hyderabad, India and included Grade five, aged 10-12 years. In order to understand the reading difficulties of English as a second language, a qualitative approach was employed. Interview, reading tes

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Publication Date
Mon Dec 21 2020
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
MONITORING OF THE WILD MAMMAL FAUNA IN BAMO MOUNTAIN IN NORTHERN IRAQ (KURDISTAN) FOR THE FIRST TIME USING CAMERA TRAP METHOD AND RAISING AWARENESS FOR ITS CONSERVATION
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Mammals are under threat worldwide due to deforestation, hunting, and other human activities. In Iraq, a total of 93 species of wild mammals have been recorded including species with global conservation concern. Bamo Mountain is situated within the Zagros Mountains in northern Iraq which is a suitable habitat for wild mammals. Due to scarcity of the field survey efforts and cryptic behavior, monitoring of the wild mammals fauna in Zagros Mountain seems challenging. Therefore, we used a camera trap which seems to be an ideal way to determine species diversity of wild mammals in Bamo Mountain. Moreover, interviews with local villagers were performed. The mammalian diversity of Bamo Mountain is not fully explored but seemed threatened by lo

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Publication Date
Sat Mar 26 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The theory of convergent between standard and optimal cost supporting actual cost in an Enterprise: بحث تطبيقي في معمل الألبسة الرجالية في النجف للفترة من 2007-2020
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The research aims to achieve proof of convergence between optimal costs and standard costs in calculating costs for the economic unit, support efforts aimed at adopting optimal costs in cost accounts and accounting thought in general, and achieve benefit from the theory of convergence between optimal costs and standard costs in the field of achieving actual costs in The economic unit in order to reduce and converge, and this came to address the possibility of adopting the concept of optimal costs in the production costs calculations for the purposes of rationalizing administrative decisions, and rationalizing the preparation of financial statements within management accounting.

The research concluded that

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Publication Date
Fri Jul 21 2023
Journal Name
Journal Of Engineering
The designed housing projects as an alternative for the informal building and their impact in addressing the heterogeneity of the urban escape in the built residential areas
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The phenomenon of informal building Spread recently in Iraqi residential areas, in general, and in Baghdad, in particular, due to the urgent housing need, on the one hand, and lack of commitment to building controls, on the other hand, to highlight the phenomenon of uncommitted building to controls and housing governing legislation in Iraq, leading to heterogeneity in both building densities and plot areas, and disorder in the urban fabric and urban escape of those areas. Research problem identified as the absence of a clear vision about the General aspects of the phenomenon of informal building in residential street scene, and the role of designed housing projects as a substitute for informal building in built residential areas. The des

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Publication Date
Mon Feb 13 2023
Journal Name
Journal Of Educational And Psychological Researches
A Blended Learning Program Based on the Next Generation Standards (NYS) to Develop the Teaching Performance of Middle School Mathematics Teachers and Some Students’ Future Thinking Skills
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Abstract

The aim of the current research is to prepare an integrated learning program based on mathematics standards for the next generation of the NYS and to investigate its impact on the development of the teaching performance of middle school mathematics teachers and the future thinking skills of their students. To achieve the objectives of the research, the researcher prepared a list of mathematics standards for the next generation, which were derived from a list of standards. He also prepared a list of the teaching competencies required for middle school mathematics teachers in light of the list of standards, as well as clarified the foundations of the training program and its objectives and the mathematical

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Publication Date
Fri Jan 01 2021
Journal Name
Anais Da Academia Brasileira De Ciências
Molecular characterization of viruses associated to leaf curl disease complex on zucchini squash in Iraq reveals Deng primer set could distinguish between New and Old World Begomoviruses
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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Designing activity based costing systems ABC for transport services and its role in improving the efficiency of pricing decisions: بحث تطبيقي في الشركة العامة لادارة النقل الخاص
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  The research dealt with the design of the cost accounting system for the transport service and its Role in improving the efficiency of pricing decisions through the application of the cost system based on ABC activities. The main activities were defined and cost guides were to measure the cost of each service and to determine the cost of each service for the purpose of providing management with appropriate information and pricing decisions The problem of research in the lack of adoption by some public companies in the service sector on the cost accounting system to calculate the cost of service as well as the lack of identification of productive activities and service activities and therefore cannot make the appropriate decision t

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