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Downlink Training Design for FDD Massive MIMO Systems in the Presence of Colored Noise
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Massive multiple-input multiple-output (MaMi) systems have attracted much research attention during the last few years. This is because MaMi systems are able to achieve a remarkable improvement in data rate and thus meet the immensely ongoing traffic demands required by the future wireless networks. To date, the downlink training sequence (DTS) for the frequency division duplex (FDD) MaMi communications systems have been designed based on the idealistic assumption of white noise environments. However, it is essential and more practical to consider the colored noise environments when designing an efficient DTS for channel estimation. To this end, this paper proposes a new DTS design by exploring the joint use of spatial channel and noise covariance matrices, when the channel is not reciprocal but the coherence block length remains limited. We derive an analytical solution for the mean square error (MSE) based on the proposed training design with colored noise. In addition, this paper exploits the method of random matrix theory to provide an analytical solution for the downlink (DL) achievable sum rate of the regularized zero forcing beamforming (RZFBF) precoder. Numerical results demonstrate that using the proposed DTS design, the MSE of the channel estimate is significantly reduced compared with the conventional training designs with white noise. Furthermore, the results show that the proposed pilot design markedly improves the DL achievable SR over the conventional training designs, especially at relatively low signal-to-noise-ratio (SNR) levels. This enables FDD MaMi systems to operate under more practical scenarios of colored noise and limited coherence time environments.

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Publication Date
Tue Mar 30 2010
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures
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The corrosion inhibition of low carbon steel in1N HCl solution in the presence of peach juice at temperature (30,40,50,and 60)°C at concentration ( 5, 10, 20, 30, 40and 50 cm3/L)were studied using weight loss and polarization techniques. Results show that the inhibition efficiency was increased with the increase of inhibitor concentration and increased with the increase of temperature up to 50ºC ,above 50ºC (i.e. at 60 ºC) the values of efficiency decreases. Activation parameters of the corrosion process such as activation energies, Ea, activation enthalpies, ΔH, and activation entropies, ΔS, were calculated. The adsorption of inhibitor follows Langmuir isotherm. Maximum inhibition efficiency obtained was a bout 91% at 50ºC in the

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Publication Date
Thu Jan 01 2015
Journal Name
Iraqi Postgraduate Medical Journal
Immunohistochemical Study of Leydig Cells in the Testicular Interstitial Tissue of Rats Treated with Tribulus Terrestris Using P450scc.
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BACKGROUND: Tribulus terrestris has been commonly used in folk medicine to energize, vitalize and improve sexual function and physical performance in men and laboratory rats. OBJECTIVE: To study the effect of Tribulus terrestris on the number of Leydig cells. MATERIALS AND METHODS: Tribulus terrestris was given to mature male rats as an oral single herbal suspension in a dose of 2.0mg /1000gbody weight for 14 days to stimulate spermatogenesis. Formalin fixed paraffinembedded tissue sections were performed for histological, immunohistochemical and morphometrical studies. RESULTS: Histological study revealed wider seminiferous tubules and increased spermatocytes population with an increased sperm density inside the lumen of the tubul

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Publication Date
Sun Sep 06 2009
Journal Name
Baghdad Science Journal
Study of R -molar ratio effect on the transformation of tetraethylorthosilicat precursor to gels in sol-gel technique
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The effect of using different R -molar ratio under variable reaction conditions (acidic as well as basic environment and reaction temperature) have been studied. The overall experiments are driven with open and closed systems. The study shows that there is an optimum value for a minimum gelling time at R equal 2. The gelling time for all studied open system found to be shorter than in closed system. In acidic environment and when R value increased from 2 to 10, the gelling time of closed systems has increased four times than open systems at T=30 ?C and fourteen times when temperature reaction increased to 60 ?C. While in basic environment the influence of increasing R value was limited.

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Publication Date
Sun Sep 07 2014
Journal Name
Baghdad Science Journal
Analysis of Fatty Acid Composition in the Seed and flower oil of Syrian Ligustrun Lucidum and olive oil
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The fatty acid composition in the seed and flower of Ligustrun lucidum and olive oil was studied by Gas Chromatography. Results showed that the main components of seed oil were Palmitic (C16:0) 5,893% ,Palmitolic acid (C16:1)0,398%, Steaeic (C18:0)2,911% ,Oleic (C18:1)74,984%,Linoleic (C18:2) 12,959%,and Linolenic (C18:3) 0,997%. The proportion of unsaturated fatty acid was above 89,338%, so the seed oil of L. lucidum ait belonged to unsaturated oil which possessed promising application. The components of flower oil were Palmitic (C16:0) 65,674% ,Palmitolic acid (C16:1)6,516%, Steaeic (C18:0)2,641% ,Oleic (C18:1)14,707%,Linoleic (C18:2) 3,113%,and Linolenic (C18:3) 2,70%. The proportion of unsaturated fatty acid and saturated fatty acid wa

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Publication Date
Sun Mar 19 2023
Journal Name
Journal Of Educational And Psychological Researches
Special Education Teachers’ Perceptions of the Factors lead to School Bullying of Students with Intellectual Disabilities in Asir
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Abstract

This study aims to identify the most prominent factors that lead to bullying of students with intellectual disabilities in primary and middle schools from the perspectives of special education teachers. A quantitative descriptive approach was utilized. A questionnaire was used as a tool for data collection. The sample consisted of (72) male and female teachers from the Asir region in the Kingdom of Saudi Arabia. The results revealed the most prominent factors that lead to bullying as follows: factors associated with the school and its policies, factors associated with peers, factors associated with students with intellectual disabilities, and factors associated with general education teachers. The findin

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Publication Date
Wed Sep 30 2020
Journal Name
Open Access Macedonian Journal Of Medical Sciences
The Prevalence of Myeloproliferative Disorders in A Group of Iraqi Patients And Its Relation To Blood Indices Parameters
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AIM: The aim of this study was to measure the prevalence of myeloproliferative disorders in a sample of Iraqi patients and to measure the changes in patients’ blood parameters. BACKGROUND: Myeloproliferative disorders are a group of neoplasms affecting the bone marrow progenitor cells characterized by excess cells with a risk of transforming to acute leukemia. There is a gap in knowledge about the prevalence of Iraqi population. Thus, we investigated the prevalence and distribution of different types of myeloproliferative disorders in a sample of Iraqi patients. MATERIALS AND METHODS: Cross-sectional study is done at the National Center of Hematology from November 2019 till March 2020 on 75 patients who were diagnosed

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Publication Date
Mon Feb 04 2019
Journal Name
Iraqi Journal Of Physics
Indoor risk assessment of radon gas in the science college buildings-University of Mustansiriyah using RAD-7 detector
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In the present work, a set of indoor Radon concentration measurements was carried out in a number of rooms and buildings of Science College in the University of Mustansiriyah for the first time in Iraq using RAD-7 detector which is an active method for short time measuring compared with the passive method in solid state nuclear track detectors (SSNTD's). The results show that, the Radon concentrations values vary from 9.85±1.7 Bq.m-3 to 94.21±34.7 Bq.m-3 with an average value 53.64±26 Bq.m-3 which is lower than the recommended action level 200-300 Bq/m3 [ICRP, 2009].
The values of the annual effective dose (A.E.D) vary from 0.25 mSv/y to 2.38 mSv/y, with an average value 1.46±0.67 mSv/y which is lower than the recommended the rang

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Publication Date
Sat Aug 22 2020
Journal Name
Multicultural Education
Effect Of Using Webinar Technique On The Digital Culture Of Chemistry Students In Ibin Haitham Pure Science College
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The aim of this research is to identify the effect of Webinar technique on digital culture in the College of Education for pure sciences at Ibin Haitham, University of Baghdad. The research samples consisted of (68) male and female students from the Chemistry Department who are following classes during the (2019- 2020) academic year. The samples represent (42%) of the total number of (162) students split into control and experimental groups. For this purpose, the scientific contents for testing were determined. The experimental part is based on analysis of the results from experiments in (preliminary standard solutions, refractive index, Beer-Lambert law). To achieve the aim of the research in testing the measure of student's digital cultur

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Publication Date
Fri Dec 31 2021
Journal Name
Review Of International Geographical Education
Investing Organizational Identity in Improving Work Teams: An Exploratory Study of a Sample of The Capital's Traffic Directorates
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The research aims to identify the role of organizational identity in improving work teams, and to suggest ways to deal with the outputs of work teams in a way that achieves the goals of the Baghdad Traffic Directorate as it is the subject of the application of the research, while the research community was represented by its officers, while the research sample was embodied in (General Director, Associate The Director General, the directors of Rusafa and Karkh traffic and their assistants, as well as the heads of the divisions and the officials of the departments) in it. The sample was (200) observations. The descriptive exploratory approach was devoted to conducting the research, relying on the questionnaire in data collection, as well as e

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Publication Date
Mon Jun 19 2023
Journal Name
Journal Of Engineering
REVIEW THE ASSESSMENT OF EFFECTS OF LOST TIME INJURIES IN AN INDUSTRIAL SYSTEM BY USING AN EXPLANATORY PROGRAM
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Health and safety problem can be described by statistics it can only be understood by knowing and feeling the pain, suffering, and depression. Health and safety has a legal responsibility to protect it for everyone who can affect in the workplace. This includes manufacturers, suppliers, designers and controllers of work places and employees. Work injury is one of the major problems in manufacturing and production systems industries; it is reduced production efficiency and affects the cost. To gain flexibility from a traditional manufacturing system and production efficiency, this paper is about the application of estimating technology to preview and synthesis of Lost Time of Work Injuries in industry systems aims to provide a safe workin

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