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Medium access control protocol design for wireless communications and networks review
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<p><span>Medium access control (MAC) protocol design plays a crucial role to increase the performance of wireless communications and networks. The channel access mechanism is provided by MAC layer to share the medium by multiple stations. Different types of wireless networks have different design requirements such as throughput, delay, power consumption, fairness, reliability, and network density, therefore, MAC protocol for these networks must satisfy their requirements. In this work, we proposed two multiplexing methods for modern wireless networks: Massive multiple-input-multiple-output (MIMO) and power domain non-orthogonal multiple access (PD-NOMA). The first research method namely Massive MIMO uses a massive number of antenna elements to improve both spectral efficiency and energy efficiency. On the other hand, the second research method (PD-NOMA) allows multiple non-orthogonal signals to share the same orthogonal resources by allocating different power level for each station. PD-NOMA has a better spectral efficiency over the orthogonal multiple access methods. A review of previous works regarding the MAC design for different wireless networks is classified based on different categories. The main contribution of this research work is to show the importance of the MAC design with added optimal functionalities to improve the spectral and energy efficiencies of the wireless networks.</span></p>

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Publication Date
Fri Jan 01 2021
Journal Name
Aip Conference Proceedings
Synthesis and characterizations of core-shell SiO2/Au/Ag nano-particles by exploding of wire and pulsed laser plasmas
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Publication Date
Thu Apr 04 2024
Journal Name
Iraqi Journal Of Applied Physics
Experimental Investigation on Mechanical and Physical Properties of Hybrid Plastic/Wood Composites as Echo-friendly Structural and Decorative Materials
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This study focuses on producing wood-plastic composites using unsaturated polyester resin reinforced with Pistacia vera shell particles and wood industry waste powder. Composites with reinforcement ratios of 0%, 20%, 30%, and 40% were prepared and tested for thermal conductivity, impact strength, hardness, and compressive strength. The results revealed that thermal conductivity increases with reinforcement, while maintaining good thermal insulation, reaching a peak value of 0.633453 W/m·K. Hardness decreased with increased reinforcement, reaching a minimum nominal hardness value of 0.9479. Meanwhile, impact strength and compressive strength improved, with peak values of 14.103 k/m² and 57.3864568 MPa, respectively. The main aim is to manu

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Publication Date
Tue Oct 04 2022
Journal Name
Azerbaijan Medical Journal
Ultrasonic fetal Doppler and growth indices and their relation to immediate neonatal outcomes in different severities of maternal anemia
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Doppler assessment may lead to intervention that reduces the risk of fetal brain damage. Aim of thestudy: to assess the relation between ultrasonic hemodynamic Doppler indices of middle cerebral and umbilical arteries (PI, RI), growth indices to immediate neonatal outcomes (weight, head & abdominal circumference, APGAR scores at 1 and 5 minutes and neonatal unit admission) in women with mild, moderate and severe anemia during pregnancy. Present study is a clinical prospective study carried out in Al-Elwiya Maternity Teaching Hospital during (January-Jun) 2019, all anemic pregnant women presented to Obstetrical wards in hospitals for emergency cesarean section were the study population. The final sample selected was 120 pregnant women. Ultra

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Publication Date
Wed Apr 12 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Science
Synthesis, Characterization and Study Biological Activity of Some New 1, 3, 4-Thiadiazole and Pyrazolone Derivatives Containing Indole Ring
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This work involves synthesis and characterization of some new 1, 3, 4-thiadiazole or pyrazoline derivatives heterocyclic containing indole ring. The new 2-amino-1, 3, 4-thiadiazole derivatives [IV] and [V] a, b were synthesized by cyclization reaction of 2-methyl-1H-indole-carbothiosemicarbazide [III] in H2SO4 acid or by reaction of indole-3-acetic acid or indole-3-butanoic acid with thiosemicarbazide in the presence of phosphorous oxychloride, respectively. Amide derivatives [VI]-[VIII] were synthesized by the reaction equimolar of 2-amino-1, 3, 4-thiadiazoles and (acetyl chloride, benzoyl chloride, anisoyl chloride and heptanoyl chloride) in DMF and pyridine as accepter. The new pyrazolone derivatives [XI] a, b were synthesized from heati

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Publication Date
Wed May 17 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Synthesis and Characterization of Some Mixed-Ligand Complexes Containing N-Acetyl Tryptophan and αPicoline with Some Metal Salts
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Some metal ions (Mn+2, Fe+2, Co+2,Ni+2,Cu+2 and Cd+2) complexes of  N-acetyl Tryptophan (AcetrpH) and  α-Picoline (α-Pic) have been synthesized and characterized on the basis of their FTIR,UV-Vis spectroscopy , conductivety measurements , magnetic susceptibility.  From the results obtained, the following general formula has suggested for the prepared complexes.            [M+2(Acetrp)2(α-Pic)2]. XH2O Where  M = Mn+2, Fe+2, Co+2,Ni+2,Cu+2 and Cd+2                         X =  0  ,    0   ,  &nb

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Publication Date
Sun Mar 13 2011
Journal Name
Baghdad Science Journal
In Vivo Toxicity Study of Nerium oleander's Leaves and Flowers Aqueous Extracts in Mice (Cytogenetic, Biochemical and Hematological Study)
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The present research was carried out to assess the toxic effect of oral administration of the aqueous extract of Nerium oleander leaves and flowers daily at doses of (25) mg/kg body weight for four weeks in mice. The toxicity of this plant parts was determined after two and four weeks by measuring the parameters of cytogenetic (mitotic index, micronucleus %), and serum levels of the hematological (RBC, Hb, WBC) and biochemical (GOT, GPT, ALT, AST) indexes in comparison with that of the control (normal saline), also clinical signs were determined. The results showed a significant decrease in mitotic index while an obvious raise was seen in micronucleus percentage in comparison with that of the control after the two periods of admini

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Publication Date
Sun Mar 13 2011
Journal Name
Baghdad Science Journal
Effect of some plant extracts on germination and seeding of Raphanus sativus and effect on surface growth ofRhizoctonia solani
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The experiment was conducted to study the effect of leaves extract of Salvia sclarea , Rosmarinus officinalis and Thymus vulgaris with 10% and 30% concentration on germination of seeds and growth of seedlings . The effect of these extracts on infection percentage of seeds decay and surface growth of Rhizoctonia solani . The results showed that the three extracts effected significantly to reduced percentage of seeds germination, acceleration of germination , promoter indicator , infection percentage of seeds decay and surface growth of R. solani especially in 30% concentration .

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Publication Date
Sun May 23 2010
Journal Name
Ibn Al- Haitham J. Fo R Pure & Appl. Sc I
Synthesis, Spectroscopic and Dyeing Performance Studies of Some New Heterocyclic Azo Dyes and Their Complexes with Selected Metal Ions
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Coupling reaction of m-and p- amino acetop henone and p-amino benzoic acid with (LHistidine) gave the new bidentate azo ligands (L1, L2 and L3). The prepared ligands were identified by FT-IR, UV-Vis, 1HNMR and GC- mass sp ectroscopic technique. Treatment of the prepared ligands with the following metal ions (CoII, NiII, CuII, ZnII, CdII and HgII) in aqueous ethanol with a 1:2 M:L ratio and at optimum pH, yielded a series of neutral complexes of the general formula [M (L)2 Cl2]. The prepared complexes were characterized by using flame atomic absorption, FT-IR, UV-Vis and 1HNMR spectroscopic methods as well as magnetic susceptibility and conductivity measurements. Chloride ion content was also evaluated by (Mohr method). The nature of the com

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Publication Date
Wed Jul 01 2015
Journal Name
Journal Of Engineering
A comparative Isothermal and Kinetic Study of the Adsorption of Lead (II) from Solution by Activated Carbon and Bentonite
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This work is aiming to study and compare the removal of lead (II) from simulated wastewater by activated carbon and bentonite as adsorbents with particle size of 0.32-0.5 mm. A mathematical model was applied to describe the mass transfer kinetic.

The batch experiments were carried out to determine the adsorption isotherm constants for each adsorbent, and five isotherm models were tested to choose the best fit model for the experimental data. The pore, surface diffusion coefficients and mass transfer coefficient were found by fitting the experimental data to a theoretical model. Partial differential equations were used to describe the adsorption in the bulk and solid phases. These equations were simplified and the

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Publication Date
Thu Nov 29 2018
Journal Name
Iraqi Journal Of Science
Petrography and Provenance of the Sandstone of Injana and Mukdadiya Formations (Upper Miocene/Pliocene) at Duhok Governorate, Northern Iraq
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A total of 23 samples are collected from Injana and Mukdadiya Formations representing: sandstone (14 samples from Injana Formation and 9 samples from Mukdadiya Formation). 19 sandstone samples are thin sectioned for petrographic study (10 thin sections from Injana and 9 thin sections from Mukdadiya) and 23 sandstone samples are selected for heavy minerals study (14 samples from Injana and 9 samples from Mukdadiya). The petrographic investigations revealed that the sandstone of Injana and Mukdadiya Formations are composed primarily of rock fragments (sedimentary, igneous and metamorphic), quartz (monocrystalline and polycrystalline) and feldspars (orthoclase, microcline and plagioclase). The matrix is subordinate and the cement is mostly

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