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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 Dec 01 2010
Journal Name
Al-khwarizmi Engineering Journal
Design and Implementation of Iraqi Virtual Library
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      In developing countries, individual students and researchers are not able to afford the high price of the subscription to the international publishers, like JSTOR, ELSEVIER,…; therefore the governments and/or universities of those countries aim to purchase one global subscription to the international publishers to provide their educational resources at a cheaper price, or even freely, to all students and researchers of those institutions. For realizing this concept, we must build a system that sits between the publishers and the users (students or researchers) and act as a gatekeeper and a director of information: this system must register its users and must have an adequate security to e

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
The Effect of Physical Environment and Crowded Classes on Academic Achievement
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The research problem can be summarized through focusing on the environment that surrounds students and class congestion, how these factors affect directly or indirectly the academic achievement of students, how these factors affect understanding the scientific material that the student receives in this physical environment, how classroom’s components such as seats, space With which the student can move, the number of students in the same class,  the lighting, whether natural or artificial, and is this lighting sufficient or not enough, the nature of the wall paint old or modern, is it comfortable for sight, the blackboard if it is Good or exhausted,  In addition to air-conditioning sets in summer and winter, this is on the on

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Publication Date
Sun Apr 07 2013
Journal Name
Journal Of Educational And Psychological Researches
Determinants of using experimental groups and choosing reasons in psychological researches
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Until The Second Half Of Nineteenth Century  , Psychology Depended On Philosophy In Its Experiences Which Means It Depend On Individuals Feelings Toward Psychological Experiences And Rapid Observation . As For The Scientific Organized Experimentation And Observation By Machines Have Been Used Later   .

The Experimentation Looking For The Cause Of  Phenomena And How Is That Happened   Also Reveal The Causal Relationship Between Among Phenomena . The Experiences In Psychology Field Include In Its Simplest Form Only One Variable ( Effective) Which Is Called Independent Variable As Well As Another Variable ( Affected )   That Called  Dependent Variable .

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Publication Date
Sat Jan 31 2026
Journal Name
Al.qadisiya Journal For The Sciences Of Physical Education
The Influence of Using Special Exercises with Weights to Develop Moments of Force to Some of the Striking Shoulder and Arm Muscles and Accuracy of the Skill of the Smash and Rectum in Volleyball
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This research is an attempt to develop exercise with weights to strengthen some of the striking muscles in the shoulder and arm and to develop the accuracy of the smash and rectum skills. The importance of this paper lies in the study of moments of force to achieve the ability to control muscular work and to explore the impact of physical and skill exercises with weights to develop moments of force for some muscles. The experimental method on a sample of players, selected according to the intentional method, including ( 9) advanced players representing Air Force Club participating in the Premier League for season 2011-2012. It is concluded that the exercises proposed have their effective impact on developing the variables of moments force f

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Publication Date
Tue Apr 30 2024
Journal Name
Iraqi Journal Of Science
Assessment of Some Physiological, Immunological and Molecular Biomarkers in Sample of Iraqi Women Undergoing Caesarean Section and Normal Delivery
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     Pregnancy and delivery are physiological conditions that are marked by abrupt alterations to hormones, immunological and molecular characters. The current study aimed to evaluate oxytocin (OT), prolactin (PRL), cortisol and insulin growth factor-2 (IGF-2) levels as physiological biomarkers; programmed cell death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1),interleukin-6 (IL-6) as immunological biomarkers, and single nucleotide polymorphisms (SNPs; rs53576 and rs2254298) of oxytocin receptor gene OXTR as molecular factors in samples of Iraqi women undergoing caesarean section (CS) and normal delivery (ND). Blood samples were collected from 96 pregnant women at term with ages ranging between 16-43 years. Regarding

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Publication Date
Wed Feb 01 2023
Journal Name
Tropical Journal Of Natural Product Research
Expression of algD Gene in Single- and Dual-Species Biofilms of Pseudomonas aeruginosa and Staphylococcus aureus Under Starvation Stress
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Dual-species biofilms of Pseudomonas aeruginosa and Staphylococcus aureus generate difficult-to-treat illnesses. Nutrition stress in biofilms affects physiology, microbial metabolism, and species interactions, impacting bacteria growth and survival. Furthermore, the function of alginate, which is encoded by the algD gene, in the production of biofilms has been established. The present study aimed at investigating the impact of starvation on algD gene expression in single-species biofilm of P. aeruginosa and dual-species biofilms of P. aeruginosa and S. aureus from hospital sewage. A total of six P. aeruginosa and six S. aureus isolates were obtained from the microbiology laboratory at the Department of Biology, College of Science, Universit

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Publication Date
Fri Jun 11 2021
Journal Name
Journal Of Baghdad College Of Dentistry
Management of trauma to the anterior segment of the maxilla: alveolar fracture and primary incisors crown and root fracture
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Background: An injury to both the primary and permanent teeth and the supporting structures is one of the most common dental problems seen in children. Splinting is usually difficult or impossible to perform in the primary dentition (due to diminutive room size and lack of patient cooperation). Healing must, therefore, occur despite mobility at the fracture line, usually resulting in interposition of connective tissue. In some instances, infection will occur in the coronal pulp. The present study reported a case of trauma to the anterior primary teeth and alveolar bone in a four year old child. The trauma has caused fracture to the crowns and roots of the primary anterior teeth. The following case was managed in a procedure that may prov

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Publication Date
Sun Sep 29 2024
Journal Name
Journal Of Global Innovations In Agricultural Sciences
The Impact of pH and Growth Phases on Photosynthetic Pigments and Carotene of Coelastrella saipanensis N. Hanagata (Scenedsmacese, Shaerophleales)
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The present study aimed to investigate the effects of level pH and the growth phases of Coelastrella saipanensis on Chlorophyll a,b, total, and Carotene. The algae were cultured in BG11 media and grown at different pH levels. We measured chlorophyll a, b, total chlorophyll, growth phases, and carotene concentrations. The results showed that at pH 8.5, the measurements of photosynthetic pigments-chlorophyll a, Chlorophyll b, and the total chlorophyll (0.183, 0.268, and 0.433 mg L-1, respectively). The highest values of chlorophyll a (0.185 mg L-1), and b (0.339 mg L-1), and the total chlorophyll (0.492 mg L-1) were recorded in the stationary phase. In addition, the study found that at pH 8.5 and the beginning of the stationary phase,

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Publication Date
Thu Dec 30 2021
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Synthesis and Characterization of Ni-WO3/Sulfated Zirconia Nano catalyst for Isomerization of N-Hexane and Iraqi Light Naphtha
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This work deals with preparation of Sulfated Zirconia catalyst (SZ) for isomerization of n-hexane model and refinery light naphtha, as well as enhanced the role of promoters to get the target with the mild condition, stability, and to prevent formation of coke precursors on strong acidic sites of the catalyst. The prepared SZ catalysts were characterization by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer –Emmett-Teller (BET) surface area analysis, Thermogravimetric Analysis (TGA), Scanning Electron Microscope (SEM) and atomic force microscopy (AFM) Analyzer. The results illustrate that the maximum conversion and selectivity for n-hexane isomerization with Ni-WSZ and operating temperature of 150 °C

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Publication Date
Tue May 30 2023
Journal Name
Iraqi Journal Of Science
Ground State Structure of Helium and Phosphorus Isotopes using the Radial Wave Functions of Harmonic-Oscillator and Hulthen Potentials
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     The ground state density distributions and electron scattering Coulomb form factors of Helium (4,6,8He) and Phosphorate (27,31P) isotopes are investigated in the framework of nuclear shell model. For stable (4He) and (31P) nuclei, the core and valence parts are studied through Harmonic-oscillator (HO) and Hulthen potentials. Correspondingly, for exotic (6,8He) and (27P) nuclei, the HO potential is applied to the core parts only, while the Hulthen potential is applied to valence parts. The parameters for HO and Hulthen are chosen to reproduce the available experimental size radii for all nuclei under study. Finally, the CO component of electron scattering charge form factors are also investigated. Unfortunately, there is no

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