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alkej-778
Comparative study of vibration analysis in rotary shafts between Rayleigh's and Dunkerley's methods
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The importance of vibrations in rotating rotors in engineering applications has been examined, as has the best approach to interpreting vibration data. The most extensively used analytical approaches for rotating shaft vibration analysis have been investigated. In this research, a detailed study was made of the Rayleigh and Dunkerley methods due to their importance in the special calculations to find the amplitude of vibrations in the rotation system. The multi-node method was used to calculate both Dunkerley's and Rayleigh's methods. An experimental platform was built to study the vibrations that occur in the rotating shafts, and the results were compared with theoretical calculations and with different distances of the bearings. It proved that there is very little error between the experimental and theoretical results. The vibration signal from the sensors was analyzed using the LABVIEW program. Rayleigh's method was compared to the exact method, and it was considered the most accurate method. It was found that it made very little difference, up to about 0.06%. As for the Dunkerley method, the difference between it and the proper method is about 4%, which is acceptable. Then a comparison was made between Rayleigh's and Dunkerley's methods, and it was found that Dunkerley's method is the most appropriate in the calculations.

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Publication Date
Tue Sep 01 2020
Journal Name
Baghdad Science Journal
Decolorization of Phenol Red Dye by Immobilized Laccase in Chitosan Beads Using Laccase - Mediator - System Model
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This work describes the enhancement of phenol red decolorization through immobilizing of laccase in chitosan and enzyme recycling. Commercial laccase from white rot fungus, Trametesversicolor (Tvlac), was immobilizedin to freshly prepared chitosan beads by using glutaraldehyde as a cross linker. Characterization of prepared chitosan was confirmed by FTIR and scanning electron microscope (SEM). Tvlac (46.2 U/mL) immobilized into chitosan beads at 0.8 % glutaraldehyde (v/v) within 24 hrs. Synthetic (HBT) and natural (vanillin) mediators were used to enhance dye decolorizoation. It was found that 89 % of phenol red was decolorized by chitosan beads within 180 min. in the absence of enzyme and mediator, while decolorization percenta

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Publication Date
Fri Oct 25 2024
Journal Name
The Review Of Contemporary Scientific And Academic Studies
The Representation of Men and Women in the Black and White Streams of the Second Wave of Feminism: A Corpus Stylistic Analysis
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Publication Date
Sat Oct 01 2022
Journal Name
Journal Of Applied Geophysics
Predicting dynamic shear wave slowness from well logs using machine learning methods in the Mishrif Reservoir, Iraq
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Publication Date
Sat Oct 01 2022
Journal Name
Journal Of Applied Geophysics
Predicting dynamic shear wave slowness from well logs using machine learning methods in the Mishrif Reservoir, Iraq
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Publication Date
Mon Jun 22 2020
Journal Name
Baghdad Science Journal
Preparation of Nanoparticles in an Eco- friendly Method using Thyme Leaf Extracts
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Colloidal silver nanoparticles were prepared by single step green synthesis using aqueous extracts of the leaves of thyme as a function of different molar concentration of AgNO3 (1,2,3,4 mM(. The Field Emission Scanning Electron Microscopy (FESEM), UV-Visible and X-ray diffraction (XRD) were used to characterize the resultant AgNPs. The surface Plasmon resonance was observed at wavelength of 444 nm. The four intensive peaks of XRD pattern indicate the crystalline nature and the face centered cubic structure of the AgNPs. The average crystallite size of the AgNPs ranged from 18 to 22 nm. The FESEM image illustrated the well dispersion of the AgNPs and the spherical shape of the nanoparticles with a particle size distribution be

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Publication Date
Wed Dec 01 2021
Journal Name
International Journal Of Research In Social Sciences & Humanities. E-issn
CONCEPTS OF LITERATURE: COMPARATIVE LITERATURE BY HENRY GIFFORD (an Article REVIEW).
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BOOK REVIEW

Publication Date
Tue Dec 01 2020
Journal Name
Journal Of Economics And Administrative Sciences
The Impact Of Knowledge Innovation On Strategic Empowerment (Comparative Field Research)
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The Innovation Of Knowledge Is An Important And A Key Element In The Progress And Business Excellence Organizations, Therefore Requires Several Elements To Help Create And Implement And Move The Innovation Process Of Knowledge, Including The Strategic Empowerment Associated With The Element Of The Process Of Strategic Momentum Engine Driven Wheel Continuous Dynamic Innovation, And Focused Research Problem By Measuring The Availability Of Strategic Empowerment When Individuals From By Senior Departments And Ways To Help Organizations To Provide Empowerment Commensurate With The Requirements Of Achieving The Goals Of Time And Place Appropriate For The Individual, And The Importance Of Research Stems From The Importance Of The Varia

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Publication Date
Sat Feb 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of some robust methods to estimate parameters of partial least squares regression (PLSR)
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   The technology of reducing dimensions and choosing variables are very important topics in statistical analysis to multivariate. When two or more of the predictor variables are linked in the complete or incomplete regression relationships, a problem of multicollinearity are occurred which consist of the breach of one basic assumptions of the ordinary least squares method with incorrect estimates results.

 There are several methods proposed to address this problem, including the partial least squares (PLS), used to reduce dimensional regression analysis. By using linear transformations that convert a set of variables associated with a high link to a set of new independent variables and unr

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Publication Date
Wed Jan 01 2020
Journal Name
Cogent Engineering
Influence of recycled concrete aggregate treatment methods on performance of sustainable warm mix asphalt
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his study aimed to investigate the usability of Recycled Concrete Aggregate (RCA) in warm mix asphalt (WMA) as the implementation of sustainable construction technology. Five replacement rates (0%, 25%, 50%, 75%, and 100%) were tested for the coarse fraction of virgin aggregate (VA) with 3 types of RCA: untreated RCA, HL-treated RCA, and HCL-treated RCA. Scanning electron microscopy (SEM) analyses were performed to investigate the surface morphology for both treated and untreated RCA. The optimum asphalt cement content for every substitution rate was determined using Marshall mix design method. Thereafter, asphalt concrete specimens were prepared using the optimum asphalt cement content, followed by the evaluation of their performance prope

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Publication Date
Sun Feb 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Climate change and dust storms in Iraq / 'Baghdad', case study
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A dust storm in Iraq is a climatic phenomenon common in arid and semi-arid regions . The frequency of the occurrence has increased drastically in the last decade and it is increasing continuously .Baghdad city like the rest of Iraq is suffering from the significant increase in dust storms . In this research , the study of the phenomenon of dust storms for all types (Suspended dust , rising dust , dust storm) , and its relationship with some climate variables (Temperature , rainfall ,wind speed) .The statement of the impact of climate change on this phenomenon to Baghdad station  for the period (1981 – 2012) . Time series has been addressing the phenomenon of storms and cli

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