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A Partial CSI Estimation Approach for Downlink FDD massive-MIMO System with Different Base Transceiver Station Topologies
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Massive multiple-input multiple-output (massive-MIMO) is a promising technology for next generation wireless communications systems due to its capability to increase the data rate and meet the enormous ongoing data traffic explosion. However, in non-reciprocal channels, such as those encountered in frequency division duplex (FDD) systems, channel state information (CSI) estimation using downlink (DL) training sequence is to date very challenging issue, especially when the channel exhibits a shorter coherence time. In particular, the availability of sufficiently accurate CSI at the base transceiver station (BTS) allows an efficient precoding design in the DL transmission to be achieved, and thus, reliable communication systems can be obtained. In order to achieve the aforementioned objectives, this paper presents a feasible DL training sequence design based on a partial CSI estimation approach for an FDD massive-MIMO system with a shorter coherence time. To this end, a threshold-based approach is proposed for a suitable DL pilot selection by exploring the statistical information of the channel covariance matrix. The mean square error of the proposed design is derived, and the achievable sum rate and bit-error-rate for maximum ratio transmitter and regularized zero forcing precoding is investigated over different BTS topologies with uniform linear array and uniform rectangular array. The results show that a feasible performance in the DL FDD massive-MIMO systems can be achieved even when a large number of antenna elements are deployed by the BTS and a shorter coherence time is considered.

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Publication Date
Tue Jun 30 2015
Journal Name
Al-kindy College Medical Journal
Estimation of vitamin E level and its relation to lipid profile in patients with type II Diabetes Mellitus
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Background: Type 2 diabetes mellitus (T2DM) is considered a global disease as it affects over 150 million people worldwide, a number that is supposed to be doubled by 2025. High glucose levels, in vitro, appear to raise the extent of LDL oxidation, and glycated LDL is more prone to oxidative modification.Objective: To investigate the relationship between serum level of vitamin E and lipid profile in patients with type II DM.Methods: This study involved 28 patients suffering from type II DM diagnosed 1-4 years ago and with age ranged from 17 -60 years old, with different residence around Basra ; In addition to 56 apparently healthy persons matched in age and sex to the patients as a control group. The medical histories were taken and Gene

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Publication Date
Sun Aug 24 2025
Journal Name
Journal Of Baghdad College Of Dentistry
A Comparative Evaluation of the Centering Ability and Canal Transportation of Simulated S-Shaped Canals Instrumented with Different Nickel –Titanium Rotary Systems
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Background: The purpose of this study was to evaluate and compare centering ability and canal transportation of simulated S-shaped canals instrumented with four different types of rotary nickel-titanium systems. Materials and Methods: Forty simulated S-shaped canals in resin blocks were divided into four groups of ten each and were instrumented to an apical size 25 by different instrumentation technique using ProTaper Universal files (group A), ProTaperNext (group B), Reciproc (group C) and WaveOne (group D).Centering ability and canal transportation was measured at (11) measuring points from D0 to D10 bysuperimposion of the pre- and post-operative images obtained by using digital camera in standardized manner. An assessment of the canals

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Publication Date
Tue Mar 20 2018
Journal Name
Offshore Technology Conference Asia
Prediction of Hydrate Phase Equilibrium Conditions for Different Gas Mixtures
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Abstract<p>Gas hydrate formation poses a significant threat to the production, processing, and transportation of natural gas. Accurate predictions of gas hydrate equilibrium conditions are essential for designing the gas production systems at safe operating conditions and mitigating the problems caused by hydrates formation. A new hydrate correlation for predicting gas hydrate equilibrium conditions was obtained for different gas mixtures containing methane, nitrogen and carbon dioxide. The new correlation is proposed for a pressure range of 1.7-330 MPa, a temperature range of 273-320 K, and for gas mixtures with specific gravity range of 0.553 to 1. The nonlinear regression technique was applie</p> ... Show More
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Publication Date
Mon Feb 18 2019
Journal Name
Iraqi Journal Of Physics
Different methods for characterizing surface roughness using laser speckle technique
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In this work, results from an optical technique (laser speckle technique) for measuring surface roughness was done by using statistical properties of speckle pattern from the point of view of computer image texture analysis. Four calibration relationships were used to cover wide range of measurement with the same laser speckle technique. The first one is based on intensity contrast of the speckle, the second is based on analysis of speckle binary image,  the third is on size of speckle pattern spot, and the latest one is based on characterization of the energy feature of the gray level co-occurrence matrices for the speckle pattern. By these calibration relationships surface roughness of an object surface can be evaluated within the

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Publication Date
Sun Sep 01 2024
Journal Name
Kufa Journal For Agricultural Sciences
Comparing Different laboratory Methods for Measuring the Feed Pellet Durability
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The experiment aimed to compare different methods of measuring the Feed pellet durability through the effect of pellet die speeds and the particle size (mill sieve holes diameter). Feed pellet durability was studied in four different ways: pellet direct measurement (%), pellet lengths (%), pellet water absorption (%), pellet durability by drop box device (%), pellet durability by air pressure device (%). Three pellet die speeds 280, 300, and 320 rpm, three mill sieve holes diameter 2, 4, and 6 mm, have been used. The results showed that increasing the pellet die speeds from 280 to 300 then to 320 rpm led to a significant decrease in the feed pellet durability by direct measurement, drop box device, and air pressure device, while pel

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Publication Date
Thu Aug 16 2012
Journal Name
Journal Of Chemical And Pharmaceutical Research
Synthesis, Characterization, Schiff Base Phenyl 2-(2-hydroxybenzylidenamino)benzoate and its complexes with LaIII,Cr III and Pr III
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The aim of the work is the synthesis and characterization of the tridentate Schiff base (HL) containing (N and O) as donor atoms type (ONO). The ligand is: (HL) phenyl 2-(2-hydroxybenzylidenamino)benzoate . This ligand was prepared by the reaction of (phenyl 2-aminobenzoate) with salicylaldehyde under reflux in ethanol and few drops of glacial acetic acid which gave the ligand (HL). The prepared ligand was characterized by (FT IR,UV–Vis) spectroscopy, Elemental analysis of carbon, hydrogen and nitrogen (C.H.N.) and melting point. The ligand was reacted with some metal ions under reflux in ethanol with (1 metal :2 ligand )mole ratio which gave complexes of the general formula: [M(L)2]Cl , M = Cr III La III and , Pr III Products were found

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Publication Date
Sun Mar 05 2017
Journal Name
Baghdad Science Journal
Synthesis and Spectral Analysis of Some Metal Ions Complexes with Mixed Ligands of Schiff Base and 1, 10-Phenanthroline
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The free Schiff base ligand (HL1) is prepared by being mixed with the co-ligand 1, 10-phenanthroline (L2). The product then is reacted with metal ions: (Cr+3, Fe+3, Co+2, Ni+2, Cu+2 and Cd+2) to get new metal ion complexes. The ligand is prepared and its metal ion complexes are characterized by physic-chemical spectroscopic techniques such as: FT-IR, UV-Vis, spectra, mass spectrometer, molar conductivity, magnetic moment, metal content, chloride content and microanalysis (C.H.N) techniques. The results show the formation of the free Schiff base ligand (HL1). The fragments of the prepared free Schiff base ligand are identified by the mass spectrometer technique. All the analysis of ligand and its metal complexes are in good agreement with th

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Publication Date
Fri Jan 01 2016
Journal Name
Ibn Al-haitham Jour. For Pure & Appl. Sci.
Synthesis and Characterization of Some New Mixed- Ligand Complexes Containing Schiff Base and 3-Picoline with Some Metal Salts
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Some metal ions (Mn+2, Co+2, Ni+2, Cu+2,Zn+2 and Cd+2) complexes of quodridentats Schiff base derived from (2-hydroxy benzaldehyde and 4,4'-methylenedianiline as primary ligand and 3-picoline (3-pic) secondary ligand have been synthesized and characterized on the basis of their 1H ,13C-NMR, FT-IR, UV-Vis spectroscopy, conductivity measurements, elemental analysis, and magnetic moments, metal to ligands ratio in all complexes has been found to be (1:1:2) (M:Schiff base:3-pic), Schiff base behaves as neutral tetra dentate ligand with (N2,O2) system from the results obtained, the following general formula has suggested for the prepared complexes [M+2(2-mbd)(3-pic)2] and octahedral stereochemistry, Where M+2 = (Mn , Co , Ni , Cu , Zn and Cd), 2

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Publication Date
Mon Mar 23 2020
Journal Name
Baghdad Science Journal
Some Metal Ions Complexes Derived From Schiff Base Ligand with Anthranillic Acid: Preparation, Spectroscopic and Biological Studies: organic chemistry
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This search includes the preparation of Schiff base ligand (SB) from condensation primary amine with vanillin. The new ligand was diagnosed by spectroscopic methods as Mass, NMR, CHN and FTIR. Ligand complexes were mixed from new (SB) and Anthranillic acid (A) with five metal (II) chlorides. The preparation and diagnosis were conducted by FTIR, CHN, UV-visible, molar conductivity, atomic absorption and magnetic moment. The octahedral geometrical shape of the complexes was proposed. The ligands and their new complexes were screened with two different types of bacteria.

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Publication Date
Fri Aug 13 2021
Journal Name
Neural Computing And Applications
Integration of extreme gradient boosting feature selection approach with machine learning models: application of weather relative humidity prediction
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