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Analytical and Numerical Tooth Contact Analysis (TCA) of Standard and Modified Involute Profile Spur Gear
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Among all the common mechanical transmission elements, gears still playing the most dominant role especially in the heavy duty works offering extraordinary performance under extreme conditions and that the cause behind the extensive researches concentrating on the enhancement of its durability to do its job as well as possible. Contact stress distribution within the teeth domain is considered as one of the most effective parameters characterizing gear life, performance, efficiency, and application so that it has been well sought for formal gear profiles and paid a lot of attention for moderate tooth shapes. The aim of this work is to investigate the effect of pressure angle, speed ratio, and correction factor on the maximum contact and bending stress value and principal stresses distribution for symmetric and asymmetric spur gear. The analytical investigation adopted Hertz equations to find the contact stress value, distribution, and the contact zone width while the numerical part depends on Ansys software version 15, as a FE solver with Lagrange and penalty contact algorithm. The most fruitful points to be noticed are that the increasing of pressure angle and speed ratio trends to minimize all the induced stresses for the classical gears and the altered teeth shape with larger loaded side pressure angle than the unloaded side one behave better than the symmetric teeth concerning the stress reduction.

 

 

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Publication Date
Wed Jan 01 2014
Journal Name
Advances In Mechanical Engineering
Experimental and Numerical Investigations of Heat Transfer Characteristics for Impinging Swirl Flow
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This paper reports experimental and computational fluid dynamics (CFD) modelling studies to investigate the effect of the swirl intensity on the heat transfer characteristics of conventional and swirl impingement air jets at a constant nozzle-to-plate distance ( L = 2 D). The experiments were performed using classical twisted tape inserts in a nozzle jet with three twist ratios ( y = 2.93, 3.91, and 4.89) and Reynolds numbers that varied from 4000 to 16000. The results indicate that the radial uniformity of Nusselt number (Nu) of swirl impingement air jets (SIJ) depended on the values of the swirl intensity and the air Reynolds number. The results also revealed that the SIJ that was fitted with an insert of y = 4.89, which correspo

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Publication Date
Mon Dec 18 2017
Journal Name
Al-khwarizmi Engineering Journal
Experimental and Numerical Study of Collector Geometry Effect on Solar Chimney Performance
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There have been many advances in the solar chimney power plant  since 1930 and the first pilot work was built in Spain (Manzanares) that produced 50 KW. The solar chimney power plant is considered of a clean power generation that needs to be investigated  to enhance the performance by studying the effect of changing the area of passage of air to enhance the velocity towards the chimney to maximize design velocity. In this experimental and numerical study, the reduction area of solar collector was investigated. The reduction area that mean changing the height of glass cover from the absorbing plate (h1=3.8cm, h2=2.6cm and h3=1.28cm). The numerical study was performed using ANSYS Fluent software package (version 14.0) to solve go

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Publication Date
Sun Apr 01 2012
Journal Name
Energy And Buildings
Experimental and numerical studies of solar chimney for natural ventilation in Iraq
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Heat transfer process and fluid flow in a solar chimney used for natural ventilation are investigated numerically and experimentally her in. Solar chimney was designed, manufactured and tested by selecting different positions of air entrance namely: bottom entrance, side entrance, and both side and bottom entrances. The effect of integrating the chimney with paraffin (phase change material) on its thermal behavior has been also investigated. CFD analysis based on finite volume method is used to predict the thermal performance, and fluid flow in two-dimensional solar chimney under unsteady state condition, to identify the effect of different parameters such as solar radiation, and inclination angle. Experimental results show that a solar chi

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Publication Date
Sat Apr 01 2017
Journal Name
Al–bahith Al–a'alami
Analytical Approaches between New Media and Traditional Media
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The research deals with an analytical approach between new media and traditional one in the light of the changes imposed by technology, which has been able to change a number of common concepts in the field of communication and media. The researcher tries to find an analytical explanation of the relationship between technology by being an influential factor in building the information society, which is the basis of new media, and the technical output that influenced the forms of social relations and linguistic construction as a human communication tool. The research deals with an analytical approach between new media and traditional one in the light of the changes imposed by technology, which has been able to change a number of comm

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Publication Date
Tue Jun 16 2026
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of tooth shape ratio on mandibular incisors arrangement in Iraqi adult subjects
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Background: This study aimed to assess the effect of tooth shape ratio on mandibular incisor arrangement. Materials and methods: The sample included dental casts of some dental students and orthodontic patients having Class I dental and skeletal patterns with normal occlusion and severe crowding. The sample was divided into two groups according to the severity of crowding into: group I had Class I normal occlusion with mild or no crowded mandibular dentition and group II had Class I malocclusion with severe crowded mandibular dentition. Each group comprising of 40 subjects (20 males and 20 females). The mesio-distal and facio-lingual crown diameters were measured manually for each cast using modified vernier caliper gauge. Descriptive sta

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Publication Date
Wed Sep 14 2016
Journal Name
Journal Of Baghdad College Of Dentistry
Tooth Wear in Relation to Selected Salivary Variables among a Group of Older Adults
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Background: Tooth wear is one of the most concerning problems of the current dental practice especially among older subjects. The aim of this study is to determine the severity of tooth wear and its relation with selected salivary variables (salivary pH and vitamin C level) among a group of older adults in Mosul city/Iraq. Materials and methods: All subjects (30 subjects) of both gender tookpart in the current study; sixteen of them were older adults (55-65 years) and compared with fourteen middle-aged adults (30-40 years) at Textile factory in Mosul city/Iraq. Unstimulated salivary samples were collected and salivary pH was immediately measured. Salivary vitamin C level was determined colormetrically. Severity of tooth wear was determined

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Publication Date
Thu Jan 24 2019
Journal Name
Al-kindy College Medical Journal
Bacterial Profile and Antimicrobial Susceptibility in Neonatal sepses, Al -Alwyia Pediatric Teaching Hospital in Baghdad
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Background: Neonatal septicemia is a major health problem in developing countries furthermore data on bacteriological profile in early onst sepses (EOS) and late neonatal sepsis (LOS) are lacking in context of  continuous change in bacteriological profile and increasing resistant strains. Objectives: The study done to determine the pattern of organisms implicated in neonatal septicemia in a neonatal care unit and to measure the degree of bacterial resistance to some antibiotics.

Type of the study : cross –sectional study.

Methods: Confirmed cases of neonatal septicemia admitted at Al-Alwyia pediatric teaching hospital for the period from January 20

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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 Sep 01 2019
Journal Name
Journal Of Physics: Conference Series
Autoantibody Profile in Systemic Lupus Erythematosus Patients
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Abstract<p>Systemic lupus erythematosus (SLE) is an autoimmune disease, in which the etiology is not well-understood; however, interactions between environmental and genetic factors in predisposed individuals have been recognized. As a consequence, immunological alternations occur and immune cells are involved, especially T and B lymphocytes that are activated to produce different immune components. Among these components are autoantibodies that react with self-antigens aside from non-self-antigens due to the proposed theory of molecular mimicry. Accordingly, the current study was designed to examine the profile of different autoantibodies in SLE patients by using the indirect membrane based enzyme immunoassay </p> ... Show More
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Publication Date
Sun Mar 03 2013
Journal Name
Baghdad Science Journal
Lipid Profile Changes in Toxoplasmosis Aborted Women
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Blood lipids are important mediators of host defense during the acute phase of innate immunity. Parasites may induce significant changes in lipid parameters, as has been shown in vitro study where substitution of serum by lipid/cholesterol in medium and in experimental models (in vivo). Thus changes in lipid profile occur in patients that having active infections with most of the parasites. Toxoplasma cannot synthesize cholesterol and depends upon acquisition of low density lipoprotein (LDL)-derived from the host cell, via endocytosis mediated by the LDL receptor or the LDL receptor-related protein.The present study is conducted to evaluate the changes in lipid profile in T. gondii infected women.A total of patients included 87 aborted wom

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