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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
Fri May 10 2019
Journal Name
International Journal Of Research In Pharmaceutical Sciences
Interleukin-1β, interleukin-6 and tumour necrosis factor-alpha levels in blood and saliva in hypothyroidism accompanied with periodontitis
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Relationship between thyroid dysfunction and periodontal disease has been mediated through an immune response. Cytokines are implicated in the initiation, consequences of immune response and a crucial role in the pathogenesis of thyroid disease, directly target thyroid follicular cells; and in the development and progression of periodontitis. This study aimed to detect cytokines levels which known to be associated with periodontitis in serum and saliva, to test the hypothesis that hypothyroidism influences the levels of biomarkers of periodontitis. Samples were collected from sixty patients with hypothyroid age ranged (20-64) years, thirty of patients were without periodontitis (group I) and 30 with periodontal disease (II); moreover, 30 su

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Publication Date
Tue Jan 01 2019
Journal Name
Plant Archives
Evaluation of water stress effect on some chemical properties of several sunflower varieties callus treated with colocynth fruit extract
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The study was carried out in plant tissue culture laboratory, University of Baghdad during the period 2017-2019, as factorial experiment in complete randomized design, to study the effect of PEG at (0, 2, 4, 6 and 8%) on physiological and chemical changes in callus of three sunflower (Ishaqi 1, Aqmar and Al-haga) induced by the cultivation of the young stem in vitro under water stress. The content of callus cells of SOD, POD, CAT and APX enzymes as well as total dissolved carbohydrate were determined as indicators to determine the effect of PEG in callus tissue cells cultivated on medium equipped with the PEG concentrations. The results showed that cultivars were differs significantly, and A-haja variety was superior in increasing SOD to 12

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Publication Date
Tue Apr 22 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of fracture strength of endodontically treated teeth restored by milled zirconia post and core with different post and core systems (An in vitro comparative study)
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Background: Restoration of root canal treated teeth with a permanent restoration affect in the success of endodontically treated teeth. This in vitro study was performed to evaluate and compare the fracture strength of endodontically treated teeth restored by using custom made zirconium posts and cores, prefabricated carbon fiber, glass fiber and zirconium ceramic posts. Materials and method: Forty intact human mandibular second premolars were collected for this study and were divided into five groups. Each group contains 8 specimens: Group1: Teeth restored with Carbon Fiber Posts; Group2: Teeth restored with Glass Fiber Posts; Group3: Teeth restored with Zirconium Ceramic prefabricated Posts; Group4: Teeth restored with Zirconium Posts

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Publication Date
Sun Sep 05 2010
Journal Name
Baghdad Science Journal
Calculation the number buildup factor of cylindrical samples for Brass, Copper & lead
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The buildup factor of cylindrical samples (shields) for Brass, Copper & lead (Brass, Cu, Pb (was studied, where buildup factor were calculated with thickness between (0-12) m.f.p. for Co60 and Cs137sources with activities (30) & (41) MBq respectively , using scintillation detector NaI(T?) with (3"×3")volume .The results shows increases of buildup factor for low atomic number(Z) samples where the energy of radiation source was constant, also shows increases of buildup factor with decreases the energy of radiation source. An empirical equation was obtained using Matlab7 program this equation have agreements with most obtained data for 96%.

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
The Relationship between Psychological Stress and Social Isolation among Displaced Secondary School Students
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The problem of the current research addressed the close link between the psychological stress and social isolation as behavior and experience, as well as, the stress of the displaced pupils by the sense of alienation and isolation from the society to which they had moved. It reflects a sense of mystery to the displaced pupils about their lives in the present and future. Therefore, the current research aims to identify the psychological presence and the level of social isolation among secondary school displaced pupils and identify whether there were statistically significant differences in the variables between the displaced pupils (males-females). Moreover, it attempts to identify the relationship between psychological stress and social

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Publication Date
Sat Jun 15 2019
Journal Name
Journal Of Baghdad College Of Dentistry
The accuracy of cone-beam computed tomography in the evaluation of boney support of teeth among patients with a unilateral cleft of lip and palate among IraqiPopulation
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Background: To evaluate the bony supports of the teeth adjacent to the area of cleft in patient with unilateral cleft lip and palate and to compare these measurements with the measurements of the same teeth in non-cleft side by using CBCT. Materials and methods: The CBCT scans of 30 patients having cleft lip( unilateral) and palate(unilateral), were analyzed and the measurements of the alveolar bony support for teeth that are adjacent to the cleft area were measured with those teeth located on opposite side (non- clef) side. For each tooth, the measurements will taken for the distance between the( cementoenamel junction) (CEJ) and the bony crest (AC) at the( buccal area) was measured and the thickness of the buccal plate At zero, one, tw

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Publication Date
Sun Mar 01 2009
Journal Name
Baghdad Science Journal
Temperature Dependence of Hall Mobility AndCarrier Concentration of pb0.55S0.45 Films
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Measurements of Hall effect properties at different of annealing temperature have been made on polycrystalline Pb0.55S0.45 films were prepared at room temperature by thermal evaporation technique under high vacuum 4*10-5 torr . The thickness of the film was 2?m .The carrier concentration (n) was observed to decrease with increasing the annealing temperature. The Hall measurements showed that the charge carriers are electrons (i.e n-type conduction). From the observed dependence on the temperature, it is found that the Hall mobility (µH), drift velocity ( d) carrier life time ( ), mean free path (?) were increased with increasing annealing temperature

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Publication Date
Wed Mar 10 2021
Journal Name
Turkish Journal Of Physiotherapy And Rehabilitation
IMPACT OF ANXIETY AND STRESS DURING PREGNANCY UPON NEONATAL OUTCOME AT MATERNITY HOSPITALS IN BAGHDAD CITY
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Objective: To assess the impact of anxiety and stress during pregnancy upon neonatal outcome Methodology: A descriptive purposive study was used to assess the impact of anxiety and stress during pregnancy upon neonatal outcome. The study was conducted from (22nd \ September \ 2020 to 15th \ February \ 2021). A non-probability sample (purposive sample) was selected from 100 women. Data were collected through an interview with the mother in the counseling clinic, during the third trimester of pregnancy, as well as after childbirth in the labour wards to assess the outcome of pregnancy. Data were analyzed through descriptive statistics (frequency and percentages). Results: The most important thing observed in this study was the n

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Publication Date
Tue Apr 22 2025
Journal Name
Iraqi Journal Of Mechanical And Material Engineering
THE INFLUENCE OF FRICTION FACTOR ON THE COMBINED CONVECTIVE AND RADIATIVE HEAT TRANSFER IN A RECTANGULAR DUCT WITH INTERIOR CIRCULAR CORE
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Publication Date
Tue Oct 01 2019
Journal Name
Biochemical And Cellular Archives
α-TOCOPHEROL FOLIAR APPLICATION CAN ALLEVIATE THE ADVERSE EFFECT OF SALINITY STRESS ON WHEAT PLANT, TRITICUM AESTIVUM L.
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Pots experiment was conducted at the greenhouse of botanical garden belong to Department of Biology, College of Education for Pure Science, Ibn-AL-Haithum, University of Baghdad, for growth season 2018-2019. The aim of the experiment was to study the effects of foliar application of a-tocopherol concentrations (0, 50, 100, 150, 200 mg.L-1) on growth parameters and the activity of some antioxidant enzymes of wheat plant irrigated with sodium chloride concentrations (0, 75, 150, 225) mM.L-1. Salinity reduced plant growth parameter, plant height, flag leaf area, flag leaf chlorophyll content and increased the activity of antioxidant enzymes, superoxide dismutase and peroxidase. Plant growth parameters were enhanced by foliar application of a-t

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