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Theoretical and Experimental Stress Analysis of Cam With Simple Harmonic Motion
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Cams are considered as one of the most important mechanical components that depends the contact action to do its job and suffer a lot of with drawbacks to be predicted and overcame in the design process. this work aims to investigate the induced cam contact and the maximum shear stress energy or (von misses) stresses during the course of action analytically using Hertz contact stress equation and the principal stress formulations to find the maximum stress value and its position beneath the contacting surfaces. The experimental investigation adopted two dimensions photoelastic technique to analyze cam stresses under a plane polarized light. The problem has been numerically simulated using Ansys software version 15 as FE solver and depending on Lagrange and Penalty contact algorithm. The effect of cam geometry, characterized by some parameters such as follower radius, face width, rise and return angles, and modulus of elasticity on the contact stress is investigated aiming  to minimize the induced stresses.

 

 

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Publication Date
Mon Jan 13 2025
Journal Name
Journal Of Baghdad College Of Dentistry
An evaluation of the influence of different finishing lines on the fracture strength of full contour zirconia CAD/CAM and heat press all-ceramic crowns
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ABSTRACT Background: One of the major problems of all ceramic restorations is their probable fracture against the occlusal forces. The objective of this in vitro study was to evaluate the effect of two gingival finishing lines (90°shoulder and deep chamfer) on the fracture resistance of full contour CAD/CAM and heat press all-ceramic crowns. Materials and Methods: Thirty two maxillary first premolars were prepared to receive full contour CAD/CAM (zolid) and heat press (Cergo Kiss) ceramic crowns using a special paralleling device (Parallel-A-Prep). The teeth were divided into four groups according to the type of finishing line prepared. Each crown was cemented to its corresponding tooth using self-etch, self-adhesive dual cure resin ceme

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Publication Date
Fri Mar 31 2017
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
The Ability of Nutrient Antioxidants to Influence Oxidative Stress and Lower the Dose of Prednisolone in Patients with Alopecia Areata
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Alopecia areata is a common disorder, hypothesized to be autoimmune in etiology. Cortisone taken orally may stimulate new hair growth. Prednisone (orally administered steroid (has proved effective for patients with alopecia areata, but its potential side effects include weight gain, metabolic abnormalities, acne and menstrual problems.

This clinical study was designed to assess the clinical significance of the nutrient antioxidants (vitamin A, vitamin E and vitamin C) in reducing the dose of corticosteroids (prednisolone), and as a consequence, their side effects in patient with alopecia. The results of this study reveal the potential clinical significance of the therapy for two months with these antioxidants in reducing the dose

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Publication Date
Wed Jun 27 2018
Journal Name
Iraqi Journal Of Science
Theoretical Study of Density Distributions and Size Radii of 8B and 17Ne
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     The proton, neutron and matter density distributions, the corresponding size radii and elastic electron scattering form factors of one-proton8B and two-proton 17Ne halo nuclei are calculated. The theoretical technique used to fulfill calculations is by assuming that both nuclei under study are composed of two main parts; the first is the compact core and the second is the unstable halo part. The single-particle radial wavefunctions of harmonic-oscillator (HO) and Woods-Saxon (WS) potentials are used to study core and halo parts, respectively. And other approach is studied by using HO potential for both core and halo parts, but using two HO size parameters for both supposed parts. The long ta

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Publication Date
Thu Aug 31 2017
Journal Name
Journal Of Engineering
Energy Analysis of Solar Collector With perforated Absorber Plate
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The thermal performance of three solar collectors with 3, 6 mm and without perforation absorber plate was assessed experimentally. The experimental tests were implemented in Baghdad during the January and February 2017. Five values of airflow rates range between 0.01 – 0.1 m3/s were used through the test with a constant airflow rate during the test day. The variation of the following parameters air temperature difference, useful energy, absorber plate temperature, and collector efficiency was recorded every 15 minutes. The experimental data reports that the increases  the number of absorber plate perforations with a small diameter is more efficient rather than increasing the hole diameter of the absorber plate with decr

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Publication Date
Mon Apr 17 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Effect of Water Stress and Hydrogen Peroxide and Potassium on the Growth and Yield of (Zea mays L.)
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An experiment was conducted in the field, Department of field crops , College of Agriculture , University of Baghdad during fall season 2011. To study the effect of interaction of water stress and hydrogen peroxide and potassium on the growth and yield of maize plant cultivar Bohooth 106. It Included the study of three levels of water stresses of 40 , 60 and 80% of the available water , (D1 , D2 and D3) respectively, three levels of hydrogen peroxide of concentrations (0 , 15 and 30 Mm), and foliar application of potassium at the concentration of 3000 mg K. L-1 K2SO4 and without applied potassium.. Split – Split with RCBD design with three replications were used. The levels of water stresses occupied the main plots , potassium lev

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Publication Date
Sun Sep 29 2019
Journal Name
Iraqi Journal Of Science
Association Between Systemic and Local Oxidative Stress of Infertile Women Undergoing Ivf/Icsi
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     Oxidative stress (OS) may affect in vitro fertilization (IVF) outcomes in infertile women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). The aim of this study is to explore the possible relationships between OS parameters in serum and follicular fluid (FF) from infertile women with male cause infertility (n=40), women with polycystic ovary syndrome (PCOS) (n=40), and women with unexplained infertility (UI)(n=45) undergoing IVF/ICSI. The collection of blood and FF samples was done at the day of oocyte aspiration. Total peroxide (TPX) level, total antioxidant capacity (TAC), and malondialdehyde (MDA) level were measured in serum and FF; whereas, glutathione-s-transf

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Publication Date
Fri May 21 2021
Journal Name
International Journal Of Pavement Research And Technology
Developing Resilient Modulus Prediction Models Based on Experimental Results of Crushed Hornfels Mixes with Different Gradations and Plasticity
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Publication Date
Mon Jan 13 2025
Journal Name
Journal Of Baghdad College Of Dentistry
The Marginal Fitness of CAD/CAM All Ceramic Crowns Constructed by Two Typesof Direct Digitization Techniques (An In Vitro Study)
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Background: In capturing a negative image, the digital impression secures a digital record for the purposeof designing and creating restorations. The introduction of scanning system presents a paradigm shift in the way of the dental impression procedure and encourages the accuracy of obtained restoration especially in the marginal area as a result of producing accurate final impression The digital system offers many advantages over the Conventional method.. The objective of this present in vitro study was to evaluate the marginal fitness of all ceramic crowns fabricated by direct digital scanning of the prepared tooth using two types of intra-oral cameras (Bluecam camera with strip light projection technique and Omnicam camera with video sa

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Publication Date
Sun Mar 03 2013
Journal Name
Baghdad Science Journal
Comparative study of oxidative stress in diabetes mellitus
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The aim of the study was comparative between oxidative stress in diabetes mellitus using the measurement of some biophysical and biochemical parameters on two groups of diabetic patients, were conducted in the Al-Yarmuk Teaching Hospital,30 patients insulin dependent diabetes mellitus (IDDM) or type 1 ,their ages ranged between (15-45) and30 patients non- insulin dependent diabetes mellitus (NIDDM) or type 2,their ages ranged between (42-65).This study has been compared with 30 healthy subjects. The present study was demonstrated to evaluate the alteration in oxidative stress as measured by plasma and red blood cells Malondialdehyde (MDA) andchanges in antioxidant mechanism as measured by plasma and red blood cells Glutathione (GSH)

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Publication Date
Sat Dec 31 2016
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Effect of In-situ Stress on Hydraulic Fractures Dimensions
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Understanding of in-situ stress profiles and orientations plays a vital role in designing a successful hydraulic fracturing treatment. This paper is an attempet to examine the effect of lithology and in situ stress on geometery of hydraulic fractures. A hydraulic fracturing design simulator software called FracproPT with various capabilities for designing most of hydraulic fracture was used for  simulate and optimize the hydraulic fracturing. For studying purpose,  three different cases of stress gradient contrast between different formations  are considered in this study (0.4, 0.5 and 0.75 psi/ft). The results obtained from the simulator showed that  lithologies surrounding the pay zone have an effect on the fracture

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