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
Sun Sep 19 2021
Journal Name
Journal Of Petroleum Research And Studies
Enhancing the Rheological Properties of Water-Based Drilling Fluid by Utilizing of Environmentally-Friendly Materials
...Show More Authors

Recently, many materials have shown that they can be used as alternatives to chemicals materials in order to be used to improve the properties of drilling fluids. Some of these materials are banana peels and corn cobs which both are considered environmentally- friendly materials. The results of the X-ray diffraction examination have proved that the main components of these materials are cellulose and hemicellulose, which contribute greatly to the increasing of the effectiveness of these two materials. Due to their distinct composition, these two materials have improved the rheological properties (plastic viscosity and yield point) and reduced the filtration of the drilling fluids to a large extent. The addition rates used for each o

... Show More
View Publication
Crossref (6)
Crossref
Publication Date
Wed Jan 01 2025
Journal Name
International Journal Of Sports, Exercise And Physical Education
The effect of compound exercises (Physical, Physiological) supported by polar m430 devices on developing explosive power in futsal players
...Show More Authors

View Publication
Crossref
Publication Date
Sun Jan 07 2024
Journal Name
Migration Letters
The Effect Of Preventive Physical Exercises Supported By Collagen Supplements And Vitamin D In Improving Some Of The Physical And Skill Abilities Of Handball Players
...Show More Authors

The purpose of this paper is to preparing preventive exercises supported by collagen supplements and vitamin D for handball players, and identify the effect of preventive physical exercises supported by collagen supplements and vitamin D on some physical and skill abilities of handball players. The researchers used the experimental method and designed two groups, one experimental and the other control, with both pre- and post-tests, to suit the nature of the research. The research community was selected from handball players (specialized school players), numbering (14), and they were divided into two groups, each group numbering (7) players. One of the most important results reached by the researcher is that: The exercises prepared by the r

... Show More
View Publication Preview PDF
Publication Date
Wed Jan 01 2025
Journal Name
International Journal Of Physiology, Sports And Physical Education
The effect of compound exercises supported by information technology (GPS Ubiko and Polar verity senses) on the development of endurance in football players
...Show More Authors

View Publication
Crossref
Publication Date
Thu Oct 01 2009
Journal Name
Iraqi Journal Of Physics
PMMA/ Anthracene Film as a Low Doses Dosimeter
...Show More Authors

A prepared PMMA/Anthracene film of thickness 70μm was irradiated under reduced pressure ~10-3 to 60Coγ-ray dose of (0.1mrad-10krad) range. The optical properties of the irradiated films were evaluated spectrophotometrically. The absorption spectrum showed induced absorption changes in the 200-400nm range. At 359nm, where there is a decrease in radiation-induced absorption, the optical density as a function of absorbed dose is linear from 10mrad-10Krad.It can therefore, be used as radiation dosimeter for gamma ray in the range 10mrd-10krad

View Publication Preview PDF
Publication Date
Sun Oct 31 2021
Journal Name
Research Journal Of Pharmacy And Technology
A Review on Film Forming Drug Delivery Systems
...Show More Authors

Conventional dosage forms for topical and transdermal drug delivery have several disadvantages related mainly to its poor skin permeation and patient compliance. Many approaches have been developed to improve these dosage forms. Film forming drug delivery systems represents a recent advancement in this field. It provides improved patient compliance with enhanced skin permeation of drugs. In its simplest form, these consist of a polymeric solution, usually in a supersaturated state, in a suitable solvent. A plasticizer is usually added to improve the flexibility and enhance the tensile strength to the film. It is also possible to control and sustain the drug release from the films by controlling the polymeric content, concentration o

... Show More
View Publication
Scopus (4)
Crossref (6)
Scopus Crossref
Publication Date
Tue Oct 30 2018
Journal Name
Iraqi Journal Of Physics
Annealing effects on optical and structural properties of chromium oxide thin film deposited by PLD technique
...Show More Authors

Optical properties of chromium oxide (Cr2O3) thin films which were prepared by pulse laser deposition method, onto glass substrates. Different laser energy (500-900) mJ were used to obtain Cr2O3 thin films with thickness ranging from 177.3 to 372.4 nm were measured using Tolansky method. Then films were annealed at temperature equal to 300 °C. Absorption spectra were used to determine the absorption coefficient of the films, and the effects of the annealing temperature on the absorption coefficient were investigated. The absorption edge shifted to red range of wavelength, and the optical constants of Cr2O3 films increases as the annealing temperature increased to 300 °C. X-ray diffraction (XRD) study reveals that Cr2O3 thin films are a

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Tue Jan 01 2019
Journal Name
Energy Procedia
Design and Construction of Nanostructure TiO2 Thin Film Gas Sensor Prepared by R.F Magnetron Sputtering Technique
...Show More Authors

In this research, Mn-doped TiO2 thin films were grown on glass, Si and OIT/glass substrates by R.F magnetron sputtering technique with thicknesses (250 nm) using TiO2:Mn target under Ar gas pressure and power of 100 Watt. Through the results of X-ray diffraction, the prepared thin films are of the polycrystallization type after the process of annealing at 600°C for two hour The average crystalline size were 145.32, 280.97 and 261.23 nm for (TiO2:Mn) thin film on glass, Si and OIT/glass substrates respectively, while the measured surface roughness is between 0.981nm and 1.14 nm. The fabricated (TiO2:Mn) thin film on glass sensors have high sensitivity for hydrogen( H2 reducing gas) compared to the sensitivity for hydrogen gas on Si and OIT/

... Show More
View Publication
Crossref (31)
Crossref
Publication Date
Sun Sep 07 2008
Journal Name
Baghdad Science Journal
Study the effect by CO2 laser on some optical properties of (Cd) thin film doping by Ni
...Show More Authors

In this research study the effect of irradiation by (CW) CO2 laser on some optical properties of (Cds) doping by Ni thin films of (1)µm thickness has been prepared by heat evaporation method. (X-Ray) diffraction technique showed the prepared films before and after irradiation are ploy crystalline hexagonal structure, optical properties were include recording of absorbance spectra for prepared films in the range of (400-1000) nm wave lengths, the absorption coefficient and the energy gap were calculated before and after irradiation, finally the irradiation affected (CdS) thin films by changing its color from the Transparent yellow to dark rough yellow and decrease the value absorption coefficient also increase the value of energy gap.

View Publication Preview PDF
Crossref
Publication Date
Sun Mar 01 2015
Journal Name
Baghdad Science Journal
Influence of MHD on Some Oscillating Motions of a Fractional Burgers' Fluid
...Show More Authors

This paper presents a study for the influence of magnetohydrodynamic (MHD) on the oscillating flows of fractional Burgers’ fluid. The fractional calculus approach in the constitutive relationship model is introduced and a fractional Burgers’ model is built. The exact solution of the oscillating motions of a fractional Burgers’ fluid due to cosine and sine oscillations of an infinite flat plate are established with the help of integral transforms (Fourier sine and Laplace transforms). The expressions for the velocity field and the resulting shear stress that have been obtained, presented under integral and series form in terms of the generalized Mittag-Leffler function, satisfy all imposed initial and boundary conditions. Finall

... Show More
View Publication Preview PDF
Crossref