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
Wed Mar 01 2023
Journal Name
Baghdad Science Journal
Stability of Complement Degree Polynomial of Graphs
...Show More Authors

     A graph is a structure amounting to a set of objects in which some pairs of the objects are in some sense related. The objects correspond to mathematical abstractions called vertices (also called nodes or points) and each of the related pairs of vertices is called an edge (also called link or line). A directed graph is a graph in which edges have orientation. A simple graph is a graph that does not have more than one edge between any two vertices and no edge starts and ends at the same vertex.  For a simple undirected graph G with order n, and let  denotes its complement. Let δ(G), ∆(G) denotes the minimum degree and maximum degree of G respectively. The complement degree polynomial of G is the polynomial CD[G,x]= , where C

... Show More
View Publication Preview PDF
Scopus (1)
Scopus Clarivate Crossref
Publication Date
Sat Feb 01 2025
Journal Name
Journal Of Dentistry
Dynamic navigation-guided robotic placement of zygomatic implants
...Show More Authors

Objectives To assess the feasibility and accuracy of a new prototype robotic implant system for the placement of zygomatic implants in edentulous maxillary models. Methods The study was carried out on eight plastic models. Cone beam computed tomographs were captured for each model to plan the positions of zygomatic implants. The hand-eye calibration technique was used to register the dynamic navigation system to the robotic spaces. A total of 16 zygomatic implants were placed, equally distributed between the anterior and the posterior parts of the zygoma. The placement of the implants (ZYGAN®, Southern Implants) was carried out using an active six-jointed robotic arm (UR3e, Universal Robots) guided by the dynamic navigation coordinate tran

... Show More
View Publication Preview PDF
Scopus (2)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Mon Jun 19 2023
Journal Name
Journal Of Engineering
Study of Dynamic Sorption in Adsorption Refrigeration Cycle
...Show More Authors

This paper shows the characteristics of temperature and adsorbed (water vapor) mass rate distribution in the adsorber unit which is the key part to any adsorption refrigeration system. The temperature profiles of adsorption/desorption phases (Dynamic Sorption) are measured experimentally under the operating conditions of 90oC hot water temperature, 30oC cooling water temperature, 35oC adsorption temperature and cycle time of 40 min. Based on the temperature profiles, The mass transfer equations for the annulus adsorbent bed are solved to obtain the distribution of adsorption velocity and adsorbate concentration using non-equilibrium
model. The relation between the adsorption velocity with time is investigated during the process of ads

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Mon Jul 01 2024
Journal Name
Journal Of Dentistry
The precision of drill calibration for dynamic navigation
...Show More Authors

Objectives To quantify the reproducibility of the drill calibration process in dynamic navigation guided placement of dental implants and to identify the human factors that could affect the precision of this process in order to improve the overall implant placement accuracy. Methods A set of six drills and four implants were calibrated by three operators following the standard calibration process of NaviDent® (ClaroNav Inc.). The reproducibility of the position of each tip of a drill or implant was calculated in relation to the pre-planned implants’ entry and apex positions. Intra- and inter-operator reliabilities were reported. The effects of the drill length and shape on the reproducibility of the calibration process were also investig

... Show More
View Publication Preview PDF
Scopus (3)
Crossref (5)
Scopus Clarivate Crossref
Publication Date
Sun Dec 07 2008
Journal Name
Baghdad Science Journal
Prepared (PbS) Thin Film Doped with (Cu) and Study Structure Properties
...Show More Authors

In this research PbS and PbS:Cu films were prepered with thicknesses (0.85±0.05)?m and (0.55±0.5)?m deposit on glass and silicon substrate respectively using chemical spray pyrolysis technique with a substrate temperature 573K, from lead nitrate salt, thiourea and copper chloride. Using XRD we study the structure properties for the undoped and doped films with copper .The analysis reveals that the structure of films were cubic polycrystalline FCC with a preferred orientation along (200) plane for the undoped films and 1% doping with copper but the orientation of (111) plane is preferred with 5% doping with the rest new peaks of films and appeared because of doping. Surface topography using optical microscope were be checked, it was found

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Dec 10 2017
Journal Name
Al-academy
Building aesthetic and expressive long shot in the film contemporary novelist
...Show More Authors

The research deals with an important detail of the joints of the film industry and television drama, which is the expression and aesthetic of the long shot, after being popularized by some directors, and that the long shot has been employed since the beginning of the cinema. But the research addresses the contemporary film and how the long shot worked. The researcher identified her goal in identifying the aesthetic and expressive of the long shot in the contemporary film, and then defined the term of the shot and the long shot.
The theoretical framework was based on two topics: the first (aesthetic and artistic expression in cinema) and the second (the long shot and the state of its construction). The researcher then chose LA LA LAND

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Jan 24 2016
Journal Name
Al-academy
Poetics transformation and structure in the film: علاءالدين عبد المجيد جاسم
...Show More Authors

is divided into two chapter:Chapter one to ensure asyslematic framework for research amd included aresearch problem and also inchuded on the importance of research and the need for him as well as to clarify. The second chapter inchuded a theoretical framework: theoretical framework has been divided into two section. The first topic: poetics transformations The second topic: poetics and scale of rheloric in the film After the comp of the theoretical framework; so the researcher analyzed the film (Antichrist) has arrived ataset of resuits was including

 

View Publication Preview PDF
Crossref
Publication Date
Fri Mar 31 2017
Journal Name
Al-khwarizmi Engineering Journal
Design of Nonlinear PID Neural Controller for the Speed Control of a Permanent Magnet DC Motor Model based on Optimization Algorithm
...Show More Authors

In this paper, the speed control of the real DC motor is experimentally investigated using nonlinear PID neural network controller. As a simple and fast tuning algorithm, two optimization techniques are used; trial and error method and particle swarm optimization PSO algorithm in order to tune the nonlinear PID neural controller's parameters and to find best speed response of the DC motor. To save time in the real system, a Matlab simulation package is used to carry out these algorithms to tune and find the best values of the nonlinear PID parameters. Then these parameters are used in the designed real time nonlinear PID controller system based on LabVIEW package. Simulation and experimental results are compared with each other and showe

... Show More
View Publication Preview PDF
Publication Date
Fri Jun 29 2018
Journal Name
Journal Of The College Of Education For Women
Tagmemic Analysis of English and Arabic Praise Poetry: A Contrastive Study
...Show More Authors

 This research provides a new method to study praise poetry that can be used as a course to teach English and Arabic to students in the College of Education. This research answers two questions:

  1. Is it possible to examine praise poetry as a tagmeme?
  2. Is this analysis of great help in teaching English and Arabic to students in the College of Education?

           The data that will be chosen for the purpose of analysis are two of Shakespeare's sonnets and two of AL Mulik's poems. The sonnets selected for this purpose are 17 and 18. AL Mulik's poems selected for the same purpose are 8 and 9.

   &nbs

... Show More
View Publication Preview PDF
Publication Date
Thu May 01 2003
Journal Name
Renewable Energy
FT-IR and XPS analysis of a-Si1-xGex:H thin films
...Show More Authors

View Publication
Scopus (15)
Crossref (13)
Scopus Clarivate Crossref