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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 used in several applications). In this case, bending tooth stress reduction is 47.05% compare with involute elliptical gear. While the reduction in bending stresses of combined elliptical gear becomes higher (52.94% lower than involute gear) when crowned involute side is the loaded side, but the contact stress reduction in this case becomes lower (20% relative to involute gear). Maximum reduction in bending stress can be obtained when single profile of DCA type is used with a reduction of 64.7% relative to involute gear. Therefore; when the application requires a high contact stress resistance, combined profile can be used with DCA side as a loaded side. While in the applications that require high bending stress resistance, DCA profile can be used.

 

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Publication Date
Fri Nov 01 2019
Journal Name
Journal Of Physics: Conference Series
The Bifurcation analysis of Prey-Predator Model in The Presence of Stage Structured with Harvesting and Toxicity
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Abstract<p>For a mathematical model the local bifurcation like pitchfork, transcritical and saddle node occurrence condition is defined in this paper. With the existing of toxicity and harvesting in predator and prey it consist of stage-structured. Near the positive equilibrium point of mathematical model on the Hopf bifurcation with particular emphasis it established. Near the equilibrium point E<sub>0</sub> the transcritical bifurcation occurs it is described with analysis. And it shown that at equilibrium points E<sub>1</sub> and E<sub>2</sub> happened the occurrence of saddle-node bifurcation. At each point the pitch fork bifurcation occurrence is not happened. </p> ... Show More
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Publication Date
Wed Jun 11 2008
Journal Name
Journal Of Al-nahrain University
ANALYSIS OF A MOLECULAR DYNAMICS SIMULATION OF THE ACETYLCHOLINESTERASE ENZYME AND ITS COMPLEX WITH (AXILLARIDINE-A) INHIBITOR
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Molecular dynamics (MD) simulations were carried out in order to investigate the binding mode of axillaridine-A at the active site of human acetylcholinesterase (AChE) enzyme. 2.0 nanosecond of MD simulations was made for the protein and the complex to dynamically explore the active site and the behavior of the ligand at the peripheral AChE binding site. These calculations for the enzyme alone showed that the active site of AChE is located at the bottom of a deep and narrow cavity whose surface is lined with rings of aromatic residues and Tyr72 is almost perpendicular to the Trp286 ring and forms a stable - interaction. The size of the active site of the complex decreases with time due to increase the interaction. Axillaridine-A forms

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Publication Date
Wed Mar 30 2022
Journal Name
Journal Of Educational And Psychological Researches
Environmental Stress and their relationship to self-rebellion for Preparatory Stage Students
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The Present research aimed at identifying:   

1- The level of environmental stress among preparatory students

2- The level of self-rebellion  among preparatory students

3- The correlation between the two variables of research (environmental stress and self-rebellion) and the extent to which the independent variable contributes to the variable of the middle school students

The current research has determined the students of the fifth stage of the preparatory stage and all the branches in the departments of education in Baghdad province the morning study for the academic

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Publication Date
Thu Nov 08 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Effectiveness of instructional intervention upon multipara women’s practices to control stress incontinence
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Objective(s): to determine the effectiveness of instruction intervention upon multipara women's practices to
control stress incontinence.
Methodology: A quasi-experimental study was carried out from (2nd) April, 2010 to 15th June, 2010. Nonprobability
(purposive sample) of (60) multiparous women was selected from Baghdad Teaching Hospital and AlElwia
Maternity Teaching Hospital in Baghdad city, the sample was divided into two groups (30) women were
considered as a study group, and another (30) were considered as the control group. An instructional intervention
was applied on the study group, while the intervention was not applied on control group. A questionnaire was
resolve as a tool of data collection to suit the p

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Publication Date
Mon Mar 13 2017
Journal Name
Journal Of Baghdad College Of Dentistry
Dental anomalies in permanent teeth and the associated etiological factors among fifteen years-old students in Basrah city\Iraq
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ABSTRACT Background: Dental anomalies of teeth are major issue that contributes to dental problems encountered in general practice. The aim of this study is to measure the prevalence of dental anomalies and the associated etiological factors among 15 years old students in Basrah city –Iraq. Materials and methods: The total sample composed of 1000 students (435 males and 565 females) from urban area selected randomly from different high schools in the city. Diagnosis of dental anomalies were recorded by present or absent, diagnosis and recording of enamel defects were done according to the criteria of WHO (1997). Results: The prevalence of hypodontia was 4.6%, Females have higher prevalence than males (5.8% females and 3.0% males), ta

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Publication Date
Tue Nov 11 2014
Journal Name
Pakistan Journal Of Biological Sciences
Effects of Local Curcumin on Oxidative Stress and Total Antioxidant Capacity in vivo Study
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Publication Date
Mon Aug 22 2022
Journal Name
Biochemical And Cellular Archives
Measurement of inflammation and oxidative stress biomarkers induced by cigarette smoke among Iraqi smokers.
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To determine the association between cigarette smoking and oxidative stress, a study was conducted in the period from January 2020 to April 2021, at College of Medicine, Al-Nahrain University, Baghdad, Iraq. The Enzyme-linked immunosorbent assay (ELISA) technique was utilized for measurement the antioxidant enzymes including: Glutathione superoxide (GPX) and catalase (CAT) and the biomarker of lipid peroxidation Malondialdehyde (MDA). Also, the gene expression of Nrf2 and HO-1were determined by using RT-PCR technique. The results indicate lower level of both GPX and CAT (p ≤ 0.001) in smokers compared with non-smokers. While the result of MDA indicate higher level in smokers (p≤0.001) compared with nonsmokers. The Nrf2 and HO-1 gene exp

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Publication Date
Thu Dec 31 2015
Journal Name
Al-khwarizmi Engineering Journal
Experimental Study and Numerical Simulation of Sheet Hydroforming Process for Aluminum Alloy AA5652
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 Abstract   

Lightweight materials is used in the sheet metal hydroforming process,  because it can be adapted to the manufacturing of complex structural components into a single body with high structural stiffness. Sheet hydroforming has been successfully developed in industry such as in the manufacturing of the components of automotive.The aim of this study is to simulate the experimental results ( such as the amount of pressure required to hydroforming process, stresses, and strains distribution)  with results  of finite element analyses (FEA)  (ANSYS 11)  for aluminum alloy (AA5652) sheets with  thickness (1.2mm) before heat treatm

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Publication Date
Sun Nov 01 2015
Journal Name
Journal Of Dentistry
New functional and aesthetic composite materials used as an alternative to traditional post materials for the restoration of endodontically treated teeth
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Objectives To tailor composites of polyethylene–hydroxyapatite to function as a new intracanal post for the restoration of endodontically treated teeth (ETT). Methods Silanated hydroxyapatite (HA) and zirconium dioxide (ZrO2) filled low-density polyethylene (LDPE) composites were fabricated by a melt extrusion process and characterised using infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The flexural strength and modulus were determined in dry state and post ageing in simulated body fluid and fractured surfaces analysed by SEM. The water uptake and radiographic appearance of the experimental composites were also measured and compared with a commercially known endodontic fibre

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Publication Date
Fri Jul 01 2016
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
STUDY THE EFFECT OF DIFFERENT TYPES OF STRESS ON SOME BLOOD CONSTITUENTS AND PLASMA BIOCHAMICALS IN MALE RATS
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    The objective of this work was to determine and compare the physiological changes in some: blood components (packed cell volume and hemoglobin) and plasma biochemical parameters (glucose, total protein, albumin, cholesterol and triglycerides) under 3 day of different types of stress: water deprivation, starvation, overcrowding and handling stress. Twenty five male Wister rats weighted 100-120 gm, were divided randomly into five groups: control, water deprivation, starvation, overcrowding and handling stress. On the third day of stress the animals anesthetized for blood collection; the results of blood component revealed a significant increase in PCV and a significant decrease in Hb of water deprivation group and starva

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