Preferred Language
Articles
/
joe-250
Dynamic Stability Analysis and Critical Speed of Rotor supported by a Worn Fluid film Journal Bearings
...Show More Authors

In this paper, the effect of wear in the fluid film journal bearings on the dynamic stability of rotor bearing system has been studied depending on the development of new analytical equations for motion, instability threshold speed and steady state harmonic response for rotor with offset disc supported by worn journal bearings. Finite element method had been used for modeling the rotor bearing system. The analytical model is verified by comparing its results with that obtained numerically for a rotor supported on the short bearings. The analytical and numerical results showed good agreement with about 8.5% percentage error in the value of critical speed and about 3.5% percentage error in the value of harmonic response. The results obtained show that the wear in journal bearing decrease the instability threshold speed by 2.5% for wear depth 0.02 mm and 12.5% for wear depth 0.04 mm as well as decrease critical speed by 4.2% and steady state harmonic response amplitude by 4.3% for wear depth 0.02 mm and decrease the critical speed by 7.1% and steady state harmonic response amplitude by 13.9% for wear depth 0.04 mm.

 

 

View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Oct 17 2019
Journal Name
International Journal Of Research In Social Sciences And Humanities
A CRITICAL DISCOURSE ANALYSIS OF RHETORICAL DEVICES OF TRUMP'S AND MAY'S SPEECHES DURING THE PERIOD 2017 TO 2019
...Show More Authors

DBNRHM Sami, International Journal of Research in Social Sciences and Humanities, 2020

View Publication
Publication Date
Sat Dec 02 2017
Journal Name
Al-khwarizmi Engineering Journal
Free Vibration Analysis for Dynamic Stiffness Degradation of Cracked Cantilever Plate
...Show More Authors

 

In the present work a dynamic analysis technique have been developed to investigate and characterize the quantity of elastic module degradation of cracked cantilever plates due to presence of a defect such as surface of internal crack under free vibration. A new generalized technique represents the first step in developing a health monitoring system, the effects of such defects on the modal frequencies has been the main key quantifying the elasticity modulii due to presence any type of un-visible defect. In this paper the finite element method has been used to determine the free vibration characteristics for cracked cantilever plate (internal flaws), this present work achieved by different position of crack. Stiffness re

... Show More
View Publication Preview PDF
Publication Date
Tue Dec 13 2022
Journal Name
Mathematical Modelling Of Engineering Problems
Dynamic Response and Reliability Analysis of Stochastic Multi-Story Frame Structures under Random Excitation
...Show More Authors

In earthquake engineering problems, uncertainty exists not only in the seismic excitations but also in the structure's parameters. This study investigates the influence of structural geometry, elastic modulus, mass density, and section dimension uncertainty on the stochastic earthquake response of a multi-story moment resisting frame subjected to random ground motion. The North-south component of the Ali Gharbi earthquake in 2012, Iraq, is selected as ground excitation. Using the power spectral density function (PSD), the two-dimensional finite element model of the moment resisting frame's base motion is modified to account for random ground motion. The probabilistic study of the moment resisting frame structure using stochastic fin

... Show More
View Publication
Scopus Crossref
Publication Date
Tue Aug 01 2023
Journal Name
Journal Of Engineering
Comparative Analysis of H2 and H∞ Robust Control Design Approaches for Dynamic Control Systems
...Show More Authors

This paper discusses using H2 and H∞ robust control approaches for designing control systems. These approaches are applied to elementary control system designs, and their respective implementation and pros and cons are introduced. The H∞ control synthesis mainly enforces closed-loop stability, covering some physical constraints and limitations. While noise rejection and disturbance attenuation are more naturally expressed in performance optimization, which can represent the H2 control synthesis problem. The paper also applies these two methodologies to multi-plant systems to study the stability and performance of the designed controllers. Simulation results show that the H2 controller tracks a desirable cl

... Show More
View Publication Preview PDF
Scopus (3)
Crossref (3)
Scopus Crossref
Publication Date
Fri Oct 01 2021
Journal Name
Theory And Practice In Language Studies
Critical Discourse Analysis and Rhetorical Tropes in Donald Trump’s First Speech to the UN
...Show More Authors

Language and politics go hand in hand and learning and comprehending political genre is to learn a language created for codifying, extending and transmitting political discourse in any text/talk. Drawing upon the theoretical framework of Fairclough’s CDA and Rhetoric, the current study aims at investigating Donald Trump’s First Speech, from the point of frequency and functions of some rhetorical strategies (Parallelism, Anaphora and the Power of Three, Antithesis and Expletive, etc.), Nominalization, Passivization, We-groups and Modality as well as Lexical and Textual Analysis, presented to the UN delivered on Sep. 19, 2017. Specifically, the study seeks to determine: (1) how President Trump succeeded in conveying his notions an

... Show More
View Publication Preview PDF
Scopus (7)
Crossref (4)
Scopus Crossref
Publication Date
Thu Jul 16 2026
Journal Name
Journal Of Physical Education
Criteria Some Power Defined By Speed Endurance In Youth Basketball
...Show More Authors

View Publication
Publication Date
Sat Dec 02 2017
Journal Name
J Fac Med Baghdad
Journal of the Faculty of Medicine-Baghdad
...Show More Authors

View Publication
Crossref
Publication Date
Sat Jan 01 2022
Journal Name
Rsc Advances
Antioxidant properties of butylated phenol with oxadiazole and hydrazone moiety at <i>ortho</i> position supported by DFT study
...Show More Authors

Two series of 1,3,4-oxadiazole derivatives at the sixth position of the 2,4-di-tert-butylphenol group were synthesized.

View Publication Preview PDF
Scopus (16)
Crossref (14)
Scopus Clarivate Crossref
Publication Date
Fri Nov 29 2019
Journal Name
Iraqi Journal Of Physics
Morphological and optical properties of V2O5:TiO2 thin film prepared by PLD technique
...Show More Authors

              In this work, pure and doped Vanadium Pentoxide (V2O5) thin films with different concentration of TiO2 (0, 0.1, 0.3, 0.5) wt  were obtained using Pulse laser deposition technique on amorphous glass substrate with thickness of (250)nm. The morphological, UV-Visible and Fourier Transform Infrared Spectroscopy (FT-IR) were studied. TiO2 doping into V2O5 matrix revealed an interesting morphological change from an array of high density pure V2O5 nanorods (~140 nm) to granular structure in TiO2-doped V2O5 thin film .Transform Infrared Spectro

... Show More
View Publication Preview PDF
Crossref (6)
Crossref
Publication Date
Thu Jun 01 2017
Journal Name
International Journal Of Advanced Research
Article Detail - International Journal of Advanced Research
...Show More Authors

The bandwidth requirements of the telecommunication network users increased rapidly during the last decades. Optical access technologies must provide the bandwidth demand for each user.The passive optical

View Publication