Preferred Language
Articles
/
alkej-294
Large Eddy Simulation in Duct Flow
...Show More Authors

In this paper, the problem of developing turbulent flow in rectangular duct is investigated by obtaining numerical results of the velocity profiles in duct by using large eddy simulation model in two dimensions with different Reynolds numbers, filter equations and mesh sizes. Reynolds numbers range from (11,000) to (110,000) for velocities (1 m/sec) to (50 m/sec) with (56×56), (76×76) and (96×96) mesh sizes with different filter equations. The numerical results of the large eddy simulation model are compared with k-ε model and analytic velocity distribution and validated with experimental data of other researcher. The large eddy simulation model has a good agreement with experimental data for high Reynolds number with the first, second and third mesh sizes and the agreement increase near the wall of the duct. The percentage error for the large eddy simulation model with experimental data of the (56×56) mesh size is less than 18 % and for the (76×76) mesh size is also less than 17% and for the (96×96) mesh size is less than 16 %. The large eddy simulation model show high stability and do not need extra differential equation like the k-ε model and a great saving in time and computer memory was achieved.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Engineering
Mathematical Model for BOD in Waste Water Discharges from Al Dora Refinery in Baghdad
...Show More Authors

This research consists of two parts, the first part concern with analyzing the collected data of BOD and COD values in discharge waste water from Al-Dora refinery during 2010 to find the relationship between these two variables The results indicates that there
is a high correlation between BOD and COD when using a natural logarithm model (0.86 ln(COD)) with correlation coefficient of 0.98. This relationship is useful in predicting the BOD value using the COD value. The second part includes analyzing collected data from the same site in order to find a relationsip between BOD and other parameters COD, Phenol(phe), Temperature(T), Oil, Sulphat(SO4),pH and Total dissolved solids( TDS) discharged from the refinery. The results indicated

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Sun Oct 06 2013
Journal Name
Journal Of Educational And Psychological Researches
Following model educational offenders in collection and Alasbaka of fifth grade students preparatory in history
...Show More Authors

Following model educational offenders in collection and Alasbaka of fifth grade students preparatory in history A. M. Dr Prepared by: Dr. Bashaer Mawloud Tawfeeq, The Center of Educational and Psychological Studies Baghdad University - There is no difference statistically significant at the 0.05 level of significance between the average scores of the following students studying using model and offenders and who are studying in the usual manner (traditional) in the collection - There is no difference statistically significant at the 0.05 level of significance between the mean scores for the following students studying using model and offenders and who are studying in the usual manner (traditional) in retention Find limits: Current search

... Show More
View Publication Preview PDF
Publication Date
Sun Jul 01 2018
Journal Name
Journal Of Educational And Psychological Researches
The effect of constructivist model of yager in acquiring the geographical concepts among first intermediate students in geography
...Show More Authors

The purpose of the study is to investigate the effect of the constructivist model of yager in acquiring the geographical concepts among first intermediate students in geography. The study was carried on based on the null hypothesis, which states, there is no significant difference at the level of (0.05) between the experimental group that follows yager model in learning the principles of geography, and the control group that studies the same subject considering the traditional methods of learning, the. To do so, a sample of (70) first-intermediate student were chosen purposefully from two random class for the academic year (2016-2017) divided into two groups. The selected schools located at Al-rusafa side in the city of Baghdad, as well

... Show More
View Publication Preview PDF
Publication Date
Mon Apr 01 2019
Journal Name
International Journal Of Electrical And Computer Engineering (ijece)
Compared to wireless deployment in areas with different environmentse
...Show More Authors

<p>In the mobile phone system, it is highly desirable to estimate the loss of the track not only to improve performance but also to achieve an accurate estimate of financial feasibility; the inaccurate estimate of track loss either leads to performance degradation or increased cost. Various models have been introduced to accurately estimate the path loss. One of these models is the Okomura / Hata model, which is recommended for estimating path loss in cellular systems that use micro cells. This system is suitable for use in a variety of environments. This study examines the comparison of path loss models for statistical analysis derived from experimental data collected in urban and suburban areas at frequencies of 150-1500 MHz

... Show More
View Publication
Crossref
Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
The Role of Islamic Banks and Private Commercial Banks in Increasing Financial Depth in Iraq
...Show More Authors

The banks mobilize savings and channel them to the economy, whether commercial or Islamic banks and thus both contribute to increasing financial depth, the objective of this paper is to measure the contribution of the Islamic banks in increase financial depth in Iraq, and compared the role played by private commercial banks in contributing to increasing financial depth in Iraq. The paper has been applying the most used indicators of financial depth that used widely in the literatures, especially those applicable with the Iraqi economy.

The paper found via using the Autoregressive Distributed Lag Model (ARDL) that Islamic banks did not contribute to increasing financial depth in Iraq, as well as for the p

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sat Apr 01 2023
Journal Name
Journal Of Natural And Applied Sciences Ural
Electron Microscope Study of Human Cerebral Cortex (Left Superior Temporal Gyrus), in Different Age Groups and Gender Electron Microscope Study of Human Cerebral Cortex (Left Superior Temporal Gyrus), in Different Age Groups and Gender
...Show More Authors

Human cerebral cortex is the outer folded neuronal layer and represents major part of the cerebrum with enormous functions. It is a laminar structure, easily visualized grossly. Previous studies showed that the Superior Temporal gyrus is one of the thickest cerebral cortex regions, reaching (about 4 mm). The Electron microscope study was made on 6 samples taken to measure the neuronal soma dimension of the large pyramidal cells present in the internal pyramidal cortical layer V in different age groups and gender. Aging process was obvious on the large pyramidal cells of the cerebral cortex, in which their neuronal soma dimensions showed shrinkage with age progression. But statistically there was no differences in the values between males an

... Show More
View Publication
Publication Date
Mon Aug 01 2016
Journal Name
Journal Of Engineering
Prediction of Monthly Fluoride Content in Tigris River using SARIMA Model in R Software
...Show More Authors

The need to create the optimal water quality management process has motivated researchers to pursue prediction modeling development. One of the widely important forecasting models is the sessional autoregressive integrated moving average (SARIMA) model. In the present study, a SARIMA model was developed in R software to fit a time series data of monthly fluoride content collected from six stations on Tigris River for the period from 2004 to 2014. The adequate SARIMA model that has the least Akaike's information criterion (AIC) and mean squared error (MSE) was found to be SARIMA (2, 0, 0) (0,1,1). The model parameters were identified and diagnosed to derive the forecasting equations at each selected location. The correlat

... Show More
View Publication Preview PDF
Publication Date
Mon Aug 01 2016
Journal Name
Journal Of Engineering
Prediction of Monthly Fluoride Content in Tigris River using SARIMA Model in R Software
...Show More Authors

The need to create the optimal water quality management process has motivated researchers to pursue prediction modeling development. One of the widely important forecasting models is the sessional autoregressive integrated moving average (SARIMA) model. In the present study, a SARIMA model was developed in R software to fit a time series data of monthly fluoride content collected from six stations on Tigris River for the period from 2004 to 2014. The adequate SARIMA model that has the least Akaike's information criterion (AIC) and mean squared error (MSE) was found to be SARIMA (2,0,0) (0,1,1). The model parameters were identified and diagnosed to derive the forecasting equations at each selected location. The correlation coefficien

... Show More
Publication Date
Wed Oct 20 2021
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Dynamics and its Effects on Saturation Region in Semiconductor Optical Amplifiers
...Show More Authors

We focus on studying the dynamics of bulk semiconductor optical amplifiers and their effects on the saturation region for short pulse that differ, however there is the same unsaturated gain for both dynamics. Parameters like current injection, fast dynamics present by carrier heating (CH), and spectra hole burning (SHB) are studied for regions that occur a response to certain dynamics. The behavior of the saturation region is found to be responsible for phenomena such as recovery time and chirp for the pulse under study.

View Publication Preview PDF
Crossref
Publication Date
Sat Dec 02 2023
Journal Name
Journal Of Engineering
Augmented Reality’s Role in Highlighting Historical Heritage / Kirkuk Citadel
...Show More Authors

Augmented Reality (AR) is one of the technological developments in recent years that uses the real world as a basic pillar and enhances it by overlaying virtual objects created by computers. The study provides an overview of the use of augmented reality technology in meeting one of the most important requirements of cultural tourism: highlighting cultural and historical heritage. Accordingly, the research problem concentrated on the lack of local literature associated with the use of augmented reality in cultural tourism. It aimed to fill this gap by building a knowledge base and demonstrating the potential of augmented reality in this field. Hence, the importance of research in drawing the attention of tourism practitio

... Show More
View Publication Preview PDF
Crossref (2)
Crossref