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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
Thu Mar 09 2017
Journal Name
University Of Baghdad
Synthesis of modified Graphene Oxide and its application as Electrochemical Sensor
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This study involved preparation of Graphene oxide (GO) and reduced graphene oxide (RGO) using Hummer method and chemical method respectively. These carbon nanomaterials were used as starting material to make novel functionalize with thiocarbohydrazide (TCH) which was prepared by reacting CS2 with hydrazine to form GO or RGO- 4-amino,5-substituted 1H,1,2,4 Triazole 5(4H) thion (ASTT) ,(GOT) and( RGOT) respectively via cyclocondensation reaction. Also MnO2 nanorod was prepared to form hybridized with GOT and RGOT. A commercial multiwall carbon nanotube (MWCNT) and functionalization with carboxylic groups' (f-MWCNT) and its nanocomposite with GOT were also prepared. All carbon nanomaterials were characterized with different techniques such as

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Publication Date
Tue Sep 19 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Bacterial Contamination of Contact Lenses Among Some Female Students and Employee of College of Education-Ibn AI­ Haitham, University of Baghdad
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During the last few yt:ars, au increase :n ut ilization   of contact  ienses (both  cosmetic and correction of refractive errors lenses) was noticed among  yotmg females, with an increase in eye infections.  The present i nvocation  was carried  out  to demonstrate  the percentage  of bacter ial contamination  of both the preservation  fluid and lens oonlainers. Fifty­ two contact lenses users among  female students and em I ployees of

college   of  Education-Ibn  Al-  Haitham   were  surveyed. Data  were

obtained  on  methodof  usage and  results  of microbial examination. The &nb

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Publication Date
Sun Jan 20 2019
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Comparison Between the MLE and Standard Bayes Estimators of the Reliability Function of Exponential Distribution
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     In this paper, a Monte Carlo Simulation technique is used to compare the performance of MLE and the standard Bayes estimators of the reliability function of the one parameter exponential distribution.Two types of loss functions are adopted, namely, squared error  loss function (SELF) and modified square error loss function (MSELF) with informative and non- informative prior. The criterion integrated mean square error (IMSE) is employed to assess the performance of such estimators .

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Publication Date
Sat Jun 14 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Immunohistochemical study of CD34 in tooth eruption by using amniotic stem cells
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Background: Tooth eruption is a more general process, however, which includes certain posteruptive tooth movements. There are two fundamental requirements for both tooth eruption to occur: (1) Require soft tissue, intervening between tooth structure and alveolar bone, which plays an important role in regulating the remodeling of adjacent tissues. (2) Require bone turnover that is temporally and spatially regulated to facilitate specific translocations of teeth through alveolar bone These amniotic stem cells are multipotent and able to differentiate into various tissues, which may be useful for human application and recently it used in many medical branches. CD34 is an endothelial marker that is extensively used in immunohistochemistry a

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Publication Date
Tue Dec 01 2020
Journal Name
Egyptian Journal Of Medical Human Genetics
Association between ABO blood groups and susceptibility to COVID-19: profile of age and gender in Iraqi patients
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Abstract<sec> <title>Background

A case-control study was performed to examine age, gender, and ABO blood groups in 1014 Iraqi hospitalized cases with Coronavirus disease 2019 (COVID-19) and 901 blood donors (control group). The infection was molecularly diagnosed by detecting coronavirus RNA in nasal swabs of patients.

Results

Mean age was significantly elevated in cases compared to controls (48.2 ± 13.8 vs. 29.9 ± 9.0 year; probability [p] < 0.001). Receiver operating characteristic anal

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Publication Date
Wed Jul 01 2020
Journal Name
Iop Conference Series: Materials Science And Engineering
Experimental and Numerical Comparison of Prestressed Perforated Concrete Rafters of Different Configurations
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Abstract<p>This paper demonstrates an experimental and numerical study aimed to compare the influence of openings of different configurations on the flexural behavior of prestressed concrete rafters. The experimental program consisted of testing six simply supported prestressed concrete rafters; 5 rafters are perforated, and the other one is solid as a reference. All rafters were tested under monotonic midpoint load. The variable which has been investigated in this work was the opening’s configuration (quadrilateral or circular) with the same upper and lower chords depths. The results indicate improvement in the beam flexural behavior using the circular openings compared to the quadrilateral o</p> ... Show More
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Publication Date
Wed Jan 01 2014
Journal Name
Al-adab Journal
Glottal Stop in R.P English and Standard Arabic with Reference to Some Other Varieties
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Publication Date
Mon Aug 01 2022
Journal Name
Journal Of Structural Engineering
Standard Pushout Tests and Design Rules for a Bolted–Welded Hybrid Demountable Shear Connector
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A bolted–welded hybrid demountable shear connector for use in deconstructable steel–concrete composite buildings and bridges was proposed. The hybrid connector consisted of a partially threaded stud, which was welded on the flange of a steel section, and a machined steel tube with compatible geometry, which was bolted on the stud. Four standard pushout tests according to Eurocode 4 were carried out to assess the shear performance of the hybrid connector. The experimental results show that the initial stiffness, shear resistance, and slip capacity of the proposed connector were higher than those of traditional welded studs. The hybrid connector was a ductile connector, according to Eurocode 4, with slip capacity higher than 6 mm. A nonli

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Publication Date
Thu May 18 2023
Journal Name
Journal Of Engineering
Experimental and Numerical Study on Cavitation Effects in Centrifugal Pumps
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Experimental and numerical investigations of the centrifugal pump performance at non-cavitating and cavitating flow conditions were carried out in the present study. Experiments were performed by applying a vacuum to a closed-loop system to investigate the effects of the net positive suction head available (NPSHa), flow rate, water temperature and pump speed on the centrifugal pump performance. Accordingly, many of the important parameters concerning cavitation phenomenon were calculated. Also, the noise which is accompanied by cavitation was measured. Numerical analysis was implemented for two phase flow (the water and its vapor) using a 2-D simulation by ANSYS FLUENT software to investigate the internal flow of centrifugal pump under c

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Publication Date
Mon Dec 11 2017
Journal Name
Al-khwarizmi Engineering Journal
Experimental and Numerical Research on Flow-Induced Vibration in Valves
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Abstract  

All central air conditioning systems contain piping system with various components, sizes, material, and layouts. If such systems in operating mode, the flow in piping system and its component such as valves can produce severe vibration due to some flow phenomenon’s. In this research, experimental measurements and numerical simulation are used to study the flow-induced vibration in valves. Computational fluid dynamics (CFD) concepts are included with one-way and two-way fluid-structure interaction concepts by using finite element software Package (ANSYS 14.57). Detection analysis is performed on flow characteristics under operation conditions and relations with structural vibration. Most of

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