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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
Tue Mar 30 2021
Journal Name
College Of Islamic Sciences
Need and transgression in Surat (Abs) Semantic grammatical study: Need and transgression in Surat (Abs)
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      The research aims to highlight the significance and composition and the diversity of meanings and the Quranic context in the necessary and transgressive verbs in Surat (Abs).

      This research consists of : a preamble , and two studies . The researcher addressed in the preliminary the importance of the phenomenon of necessity and infringement, the signs of the necessary action , the structure and controls of the act , the methods of infringement , its sections and signs.

      As for the first topic : The researcher addressed the necessary verbs in Surat Abs , an applied study in terms of grammati

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Publication Date
Mon Dec 20 2021
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
STUDY THE PHYSICAL AND CHEMICAL PROPERTIES AND DETERMINATION THE CYTOTOXICITY OF KOJIC ACID PRODUCED FROM THE LOCAL ISOLATE ASPERGILLUS FLAVUS WJF81 AND THEIR EFFECTS ON CONSUMER HEALTH.: STUDY THE PHYSICAL AND CHEMICAL PROPERTIES AND DETERMINATION THE CYTOTOXICITY OF KOJIC ACID PRODUCED FROM THE LOCAL ISOLATE ASPERGILLUS FLAVUS WJF81 AND THEIR EFFECTS ON CONSUMER HEALTH.
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Steps were taken to obtain the Kojic acid crystals from local fungal isolation A. flavus WJF81 by separating the fermentation products from the fungus mycelium from the production plant at the centrifuge at a speed of 5000 cycles for 10 minutes. The extraction was followed by ethyl acetate then supernatant concentrate by using rotary evaporator, and dried with heat oven 37ºC. Long, yellowish, pristine acid crystals were obtained that examined the optical microscope with a magnification force of 10x and 40x. The melting point of kojic acid was determined between 152.9-153.5 °C Results of the diagnosis of Kojic acid by applying High pressure liquid chromatography HPLC technique showed that the acid was at one peak, which was close to the

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Publication Date
Thu Oct 01 2020
Journal Name
International Journal Of Engineering
Vertical and Lateral Displacement Response of Foundation to Earthquake Loading
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Risks are confronting the foundations of buildings and structures when exposed to earthquakes which leads to high displacements that may cause the failure of the structures. This research elaborates numerically the effect of the earthquake on the vertical and lateral displacement of footing resting on the soil. The thickness of the footing and depth of soil layer below the footing was taken as (0.5, 1.0, and 2.0 m) and (10, 20 and 40m), respectively. The stiffness ratio of soil to footing was also elaborated at 0.68, 0.8, 1.0, and 1.7. The results showed an increase in the verticle displacement of footing as the duration of the earthquake increases. The increase of soil layer thickness below the footing leads to a reduction in the vertical

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Publication Date
Thu Apr 18 2013
Journal Name
International Journal Of Computer Applications
Design and Simulation of Hartley based Multi Orthogonal Band OFDM
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Recent advances in wireless communication systems have made use of OFDM technique to achieve high data rate transmission. The sensitivity to frequency offset between the carrier frequencies of the transmitter and the receiver is one of the major problems in OFDM systems. This frequency offset introduces inter-carrier interference in the OFDM symbol and then the BER performance reduced. In this paper a Multi-Orthogonal-Band MOB-OFDM system based on the Discrete Hartley Transform (DHT) is proposed to improve the BER performance. The OFDM spectrum is divided into equal sub-bands and the data is divided between these bands to form a local OFDM symbol in each sub-band using DHT. The global OFDM symbol is formed from all sub-bands together using

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Publication Date
Thu Jun 01 2023
Journal Name
Journal Of Engineering
Integration Building Information Modeling and Lean Construction Technologies in the Iraqi Construction Sector: Benefits and Constraints
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Building Information Modeling (BIM) and Lean Construction (LC) are two quickly growing applied research areas in construction management. This study focuses on identifying the most essential benefits and analyzing the most affecting constraints on the construction sector that construction players face as they attempt to combine BIM-LC in Iraqi construction. Experts assessed 30 benefits and 28 constraints from examining the previous literature, and a two-round Delphi survey formed the responses. Expert consensus analysis was utilized to elaborate and validate responses after descriptive statistical checks had been used for data processing.

According to the study's findings, the benefits include ensuring the most ef

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Publication Date
Wed May 01 2019
Journal Name
Journal Of The College Of Education For Women
The Complex Relationship Between Darwinism, Geopolitics and Geographic Colonization Research the Relationship Between Geopolitics and Ethnography
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Research on geopolitical and geopolitical studies relates to a range of sciences that can be called auxiliary sciences, such as political science, international relations in particular, and history, but their focus is rarely on science and ethnography

That the issues and problems of the world today has become so large and complex that does not allow a specific field or knowledge to solve one of the need for the newly known knowledge integration (geopolitics and geopolitics) in particular to move towards cognitive integration to understand many of the problems and global issues that faced The importance of this study comes to clarify the relationship between Darwinism, geopolitics and geopolitics. The geopolitics in modern terms d

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Publication Date
Sun Sep 03 2017
Journal Name
Baghdad Science Journal
Kinetic and Mechanistic Studies for the Gas-phase Reaction of Ozone with 2, 3-Dimethyl-2-Butene and 1, 3-Butadiene
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The reactions of ozone with 2,3-Dimethyl-2-Butene (CH3)2C=C(CH3)2 and 1,3-Butadiene CH2=CHCH=CH2 have been investigated under atmospheric conditions at 298±3K in air using both relative and absolute rate techniques, and the measured rate coefficients are found to be in good agreement in both techniques used. The obtained results show the addition of ozone to the double bond in these compounds and how it acts as function of the methyl group substituent situated on the double bond. The yields of all the main products have been determined using FTIR and GC-FID and the product studies of these reactions establish a very good idea for the decomposition pathways for the primary formed compounds (ozonides) and give a good information for the effe

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Publication Date
Sun Mar 04 2012
Journal Name
Baghdad Science Journal
Levels of Elements in Milk and Yoghurt
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This study aimed to know the concentration of elements content in dairy products. Nine samples collected from the local market in Baghdad, two samples of milk and seven of yoghurt.The results were followed: The ratio of Aluminum In Aluminum cans That is used for storage milk and industrialize yoghurt is about 95.5% ,this ratio is against [1] which said that pureness of Aluminum used in Aluminum cans should not be less than 98-99% . and the ratio of Cadmium reached to 0.001% which is also against [1] which assure that the Aluminum cans should be clean from that element, mean while the concentration of Iron, Copper and Zinc were within the standard level. The highest concentration of Iron was in treatment B2(canon yoghurt)it was 9.95 m

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Publication Date
Sun Dec 01 2002
Journal Name
Iraqi Journal Of Physics
FLUORESCENCE LIFETIME MEASUREMENT OF C5H6 AND C6D6
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Absorption and lifetime measurements were made for C6H6. and C6D6 molecules in pure solid phase and in solid matrices of Ar, N2, CO, and CO2. All measurement are made at low temperatures ranging between 12-50 K. A modified least square fitting deconvolution was utilized to measure the fluorescence lifetime with an error less than 1%. The results show that the use of matrix isolation technique offer a unique environment that minimize the perturbation of the molecular or atomic system and hence facilitate spectral analysis.

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Synthesis of New Amide and ThioUrease Compounds.
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The reaction of some new Schiff bases ( 2-[(2-Amino – ethylimino)-methyl]-R , 2-({2-[(R-benzylidene)-amino]-ethylimino}-methyl)-R with Benzoyl chloride or Acetyl chloride were carried out. Subsequent reactions of these products N-(2-Amino-ethyl)-N-[Chloro-(R) –methyl]-benzamide or N-(2-{?-[chloro-(R) –methyl]-amino}-ethyl)-N-[chloro-(R) –methyl]- benzamide with thiourea afforded thioureas compounds. The synthesized compounds were confirmed by their IR,UV,spectra and C.H.N. analysis.

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