Preferred Language
Articles
/
alkej-211
Effect of Bearing Compliance on Thermo-hydrodynamic Lubrication of High Speed Misaligned Journal Bearing Lubricated with Bubbly Oil
...Show More Authors

Abstract

In the present work  the effect of bearing compliance on the performance of high speed misaligned journal bearing lined with a compliant PTFE liner lubricated with bubbly oil at high speeds has been studied. The effect of induced oil film temperature due to shearing effect has been implemented. Hydrodynamic effect of the complaint bearing and the influence of aerated oil have been examined by the classical thermohydrodynamic lubrication theory modified to include the effect of oil film turbulence and oil film temperature with suitable models for bubbly oil viscosity and density. The effect of liner elastic deformation has been implemented by using Winkler model. The effects of variable density and specific heat on the most importantbearing parameters such as maximum pressure, maximum temperature, bearing load carrying capacity and power losses have been investigated.The results obtained show that the oil film pressure and load carrying capacity increased for the bearing lubricated with bubbly oil of higher aeration level and smaller size of air bubbles. Including the effect of elastic deformation of the bearing liner reduces the oil film pressure, load carrying capacity and frictional power loss for the misaligned bearing working at the same circumstances

Keywords: Journal bearings, hydrodynamic lubrication, THD, compliant effect, bubbly oil, misalignment effect.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Wed Mar 20 2019
Journal Name
Al-khwarizmi Engineering Journal
Enhancement of Heat Exchanger Performance by Using Dimpled Tube
...Show More Authors

The enhancement of heat exchanger performance was investigated using dimpled tubes tested at different Reynolds numbers, in the present work four types of dimpled tubes with a specified configuration manufactured, tested and then compared performance with the smooth tube and other passive techniques performance. Two dimpled arrangements along the tube were investigated, these are inline and staggered at constant pitch ratio X/d=4, the test results showed that Nusselts number (heat transfer) of the staggered array is higher than the inline array by 13%.  The effect of different depths of the dimple (14.5 mm and 18.5 mm) has been also investigated; a tube with large dimple diameter enhanced the Nusselts number by about 25% for the ran

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Fri May 19 2023
Journal Name
Revista Iberoamericana De PsicologÍa Del Ejercicio Y El Deporte
The Effect of a Training Curriculum According To the Physiological Index and the Transitional Speed of the 100m Hurdles Runner
...Show More Authors

Recently, that there has been a decline in the levels of female players for this event in recent years compared to developments in the world, as this activity depends to achieve the highest level of performance on the physical capabilities and physiological indicators of the player who It is reflected in the achievement, which results in the loss of time for Iraqi female runners compared to the world champions in the (100) meter hurdles competition, which reflects on the level of achievement. The two researchers used the experimental approach in addressing the research problem, and the experimental design used the method of the two equal groups, the two experiments with the pre and post-tests. Female runner and second experimental group (4)

... Show More
View Publication Preview PDF
Scopus
Publication Date
Thu Apr 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of organizational stress on the Performance of professor at the Faculty of Economics and Commercial Sciences / University of Djelfa / Algeria
...Show More Authors

The present study aims at identifying the effect of organizational pressure with its aspects (management, work team, nature and conditions of work, external environment) on job performance in all its dimensions (commitment and effort made, capabilities and the rapidity of performance, motivation and job satisfaction, work environment) for the university teacher at the Faculty of Economics, Commercial and Management Sciences at the University of Djelfa, Algeria.

     In this research, the descriptive analytical approach is used. Data was collected through the distribution of a questionnaire to a sample that included 130 permanent teachers before being analyzed using the (SPSS) statisti

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Jul 02 2006
Journal Name
Journal Of The Faculty Of Medicine Baghdad
a placebo control study of the effect of nigella sativa fixed oil on the healing rate of recurrent aphthous ulceration
...Show More Authors

View Publication
Crossref
Publication Date
Sat Mar 01 2014
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Activating Financial Performance Measures On The Basis Of Value And Its Reflection On Companies Performance Under The Governance: An Applied Study On A sample Of Companies Listed In the Iraqi Stock Exchange
...Show More Authors

Increased attention to corporate governance with the increasing need for investors and other parties in the Iraqi market for securities of the information credible and confidence and greater transparency in the disclosure as well as the systems of governance lead to raise the value of the company and that by reducing the cost of capital and reduce the cost of financing, as well as that there are indications modern measurement can be adopted by the Iraqi market for securities for the purpose of evaluating the performance of listed companies and then raise their value.

   The research problem is that there is no framework or structure of the legal and local rules for the application of corporate governance in Iraq obliges

... Show More
View Publication Preview PDF
Publication Date
Mon Jul 01 2019
Journal Name
Iop Conference Series: Materials Science And Engineering
Wells location effect on the underground gas storage in UM ERadhuma Formation-Ratawie oil field
...Show More Authors

View Publication
Scopus Crossref
Publication Date
Thu Oct 08 2020
Journal Name
Journal Of Legal Sciences
The Impact of Coronavirus on the Implementation of Contractual Obligations
...Show More Authors

The global health crisis resulting from the spread of the Corona virus, which the World Health Organization described on January 30, 2020 as a public health emergency of international concern, then returned to describe it as a pandemic on March 11, 2020, and the measures and procedures taken by government authorities in different countries of the world, whether at the highest level of imposing a comprehensive curfew or what is called globally home quarantine and thus disrupting all sectors and activities in the state, whether public or private (with the exception of some sectors such as the health, media and security sectors), or at a lower level than that, such as reducing work rates in different sectors by rates that vary from one country

... Show More
View Publication
Publication Date
Sun Dec 01 2019
Journal Name
Baghdad Science Journal
Histological and Physiological Studies on the Long-term Effect of Different Concentrations of Energy Drink (Tiger) on the Renal and Hepatic Systems of Young Mice
...Show More Authors

The present study aims to investigate the long-term histopathological, and physiological effects of different concentrations of a commercially available energy drink (Tiger) on liver and kidney of young mice. Sixteen Balb/c male mice,6 -week old, were divided into 4 groups (n=4). Two groups consumed the energy drink at a concentration of 28µl energy drink/ml water. One group were killed after 10 days (T1), another group were killed after 20 days (T2). Other group of mice consumed the energy drink at a final concentration of 14µl/ml for 20 days (T3). The last group was provided only with water and served as control. Mice of all groups drank around 3 ml per day. The histopathological study on liver of treated groups showed many changes s

... Show More
View Publication Preview PDF
Scopus (9)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Fri Dec 20 2019
Journal Name
Iet Circuits, Devices & Systems
Multi‐bit error control coding with limited correction for high‐performance and energy‐efficient network on chip
...Show More Authors

In the presence of deep submicron noise, providing reliable and energy‐efficient network on‐chip operation is becoming a challenging objective. In this study, the authors propose a hybrid automatic repeat request (HARQ)‐based coding scheme that simultaneously reduces the crosstalk induced bus delay and provides multi‐bit error protection while achieving high‐energy savings. This is achieved by calculating two‐dimensional parities and duplicating all the bits, which provide single error correction and six errors detection. The error correction reduces the performance degradation caused by retransmissions, which when combined with voltage swing reduction, due to its high error detection, high‐energy savings are achieved. The res

... Show More
View Publication
Scopus (2)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Sun Feb 25 2024
Journal Name
Baghdad Science Journal
An exploratory study of history-based test case prioritization techniques on different datasets
...Show More Authors

In regression testing, Test case prioritization (TCP) is a technique to arrange all the available test cases. TCP techniques can improve fault detection performance which is measured by the average percentage of fault detection (APFD). History-based TCP is one of the TCP techniques that consider the history of past data to prioritize test cases. The issue of equal priority allocation to test cases is a common problem for most TCP techniques. However, this problem has not been explored in history-based TCP techniques. To solve this problem in regression testing, most of the researchers resort to random sorting of test cases. This study aims to investigate equal priority in history-based TCP techniques. The first objective is to implement

... Show More
View Publication Preview PDF
Scopus (1)
Crossref (1)
Scopus Crossref