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Connectivity and rendezvous in distributed DSA networks
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In this paper, we use concepts and results from percolation theory to investigate and characterize the effects of multi-channels on the connectivity of Dynamic Spectrum Access networks. In particular, we focus on the scenario where the secondary nodes have plenty of vacant channels to choose from-a phenomenon which we define as channel abundance. To cope with the existence of multi-channels, we use two types of rendezvous protocols: naive ones which do not guarantee a common channel and advanced ones which do. We show that, with more channel abundance, even with the use of either type of rendezvous protocol, it becomes difficult for two nodes to agree on a common channel, thereby potentially remaining invisible to each other. We model this invisibility as a Poisson thinning process and show that invisibility is even more pronounced with channel abundance. Following the disk graph model, we define and characterize connectivity of the secondary network in terms of the available number of channels, deployment densities, number of transceivers per node, and communication range. When primary users are absent, we derive the critical number of channels which maintains super-criticality of the secondary network. When primary users are present, we characterize and analyze the connectivity for all the regions: channel abundance, optimal, and channel deprivation. Our results can be used to decide on the goodness of any channel rendezvous algorithm by computing the expected resultant connectivity.

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Publication Date
Mon Jun 10 2024
Journal Name
Iraqi Journal For Computer Science And Mathematics
Solving tri-criteria: total completion time, total late work, and maximum earliness by using exact, and heuristic methods on single machine scheduling problem
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The presented study investigated the scheduling regarding  jobs on a single machine. Each  job will be processed with no interruptions and becomes available for the processing at time 0. The aim is finding a processing order with regard to jobs, minimizing total completion time , total late work , and maximal tardiness  which is an NP-hard problem. In the theoretical part of the present work, the mathematical formula for the examined problem will be presented, and a sub-problem of the original problem of minimizing the multi-objective functions  is introduced. Also, then the importance regarding the dominance rule (DR) that could be applied to the problem to improve good solutions will be shown. While in the practical part, two

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Publication Date
Thu Feb 01 2024
Journal Name
Journal Of Materials Science
Investigations on TiO2–NiO@In2O3 nanocomposite thin films (NCTFs) for gas sensing: synthesis, physical characterization, and detection of NO2 and H2S gas sensors
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Publication Date
Sat Jun 04 2022
Journal Name
Journal Of Inorganic And Organometallic Polymers And Materials
Improving the Mechanical Properties, Roughness, Thermal Stability, and Contact Angle of the Acrylic Polymer by Graphene and Carbon Fiber Doping for Waterproof Coatings
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Publication Date
Wed Jun 29 2022
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Kinetics and Energetic Parameters Study of Phenol Removal from Aqueous Solution by Electro-Fenton Advanced Oxidation Using Modified Electrodes with PbO2 and Graphene
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The Electro-Fenton oxidation process is one of the essential advanced electrochemical oxidation processes used to treat Phenol and its derivatives in wastewater. The Electro-Fenton oxidation process was carried out at an ambient temperature at different current density (2, 4, 6, 8 mA/cm2) for up to 6 h. Sodium Sulfate at a concentration of 0.05M was used as a supporting electrolyte, and 0.4 mM of Ferrous ion concentration (Fe2+) was used as a catalyst. The electrolyte cell consists of graphite modified by an electrodepositing layer of PbO2 on its surface as anode and carbon fiber modified with Graphene as a cathode. The results indicated that Phenol concentration decreases with an increase in current dens

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Publication Date
Thu Dec 31 2020
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
SYNTHESISAND STUDY OF THE COMPLEXES OF: N-(3,4,5-TRIMETHOXY PHENYL)-N- BENZOYL THIOUREA (TMPBT) WITH A NUMBER OF TRANSITION METALS AND THEIR INDUSTRIAL AND MEDICAL IMPORTANCE: SYNTHESISAND STUDY OF THE COMPLEXES OF: N-(3,4,5-TRIMETHOXY PHENYL)-N- BENZOYL THIOUREA (TMPBT) WITH A NUMBER OF TRANSITION METALS AND THEIR INDUSTRIAL AND MEDICAL IMPORTANCE
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This paper performance for preparation and identification of six new complexes of a number of transition metals Cr (lII), Mn (I1), Fe (l), Co (II), Ni (I1), Cu (Il) with: N - (3,4,5-Trimethoxy phenyl-N - benzoyl Thiourea (TMPBT) as a bidentet ligand. The prepared complexes have been characterized, identified on the basis of elemental analysis (C.H.N), atomic absorption, molar conductivity, molar-ratio ,pH effect study, I. Rand UV spectra studies. The complexes have the structural formula ML2X3 for Cr (III), Fe (III), and ML2X2 for Mn (II), Ni (II), and MLX2 for Co (Il) , Cu (Il).

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Publication Date
Mon Jan 01 2024
Journal Name
2nd International Conference For Engineering Sciences And Information Technology (esit 2022): Esit2022 Conference Proceedings
Determination of moisture content in some materials using linear attenuation coefficient
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Publication Date
Thu Nov 08 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Evaluation of nurses' practices toward postoperative wound dressing in surgical wards
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Objective(s): The study aimed to assess the level of nursing performance and practices in terms of approaching or
distancing itself from the optimal performance criteria universally adopted within the variable dressing surgical
wounds of patients admitted to the surgical wards, and determine the relationship between the level of nurse's
performance and socio-demographic characteristics of them in those wards.
Methodology: A descriptive assessing design was adopted from November the 10th, 2010 until June the 1st, 2011 to
assess the nursing care provided practices for the postoperative period within the variable dressing surgical wounds in
the complex of Medical City. Whereas the study was conducted in three hospitals; Ba

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Publication Date
Mon Aug 19 2024
Journal Name
Journal Of Ovonic Research
Synthesis of PPy- Nd2O3 nano-composite for utilization in supercapacitor applications
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In this study, chemical oxidation was employed for the synthesis of polypyrrole (PPy) nanofiber. Furthermore, PPy has been subjected to treatment using nanoparticles of neodymium oxide (Nd2O3), which were produced and added in a certain ratio. The inquiry centered on the structural characteristics of the blend of polypyrrole and neodymium oxide after their combination. The investigation utilises X-ray diffraction (XRD), FTIR, and Field Emission Scanning Electron Microscopy (FE-SEM) for PPy, 10%, 30%, and 50% by volume of Nd2O3. According to the electrochemical tests, it has been noted that the nanocomposites exhibit a substantial amount of pseudocapacitive activity.

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Publication Date
Wed May 18 2016
Journal Name
Al-academy
The Role of Phenotypic Traits in Interior Spaces: سهير ياسين احمد
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The phenotypic characteristics in the interior spaces are seeing the result of the ability of the designer in his handling of the vocabulary and the elements to deliver a specific meaning for the recipient , and is working to stir up the receiver and make it effective in the process of perception of space. So the theme of the role of phenotypic characteristics is of great significance in the process of analyzing spaces to reach the goal of the main idea , and show those qualities through relationships design in terms of shape, color and texture ... etc. , to reach also designs more beautiful , and creating an internal environment , creative and continuous with its external environment , Hence the importance of research in that it tries t

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Publication Date
Sun Dec 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Catalytic Wet Air Oxidation of Phenol in a Trickle Bed Reactor
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Catalytic wet air oxidation of aqueous phenol solution was studied in a pilot plant trickle bed reactor using copper
oxide catalyst supported on alumina and silica. Catalysts were prepared by impregnating method. Effect of feed solution
pH (5.9, 7.3, and 9.2), gas flow rate (20%, 50%, 80%, and 100%), WHSV (1, 2, and 3 h-1), temperature (120°C, 140°C,
and 160°C), oxygen partial pressure (6, 9, 12 bar), and initial phenol concentration (1, 2, and 4 g/l).Generally, the
performance of the catalysts was better when the pH of feed solution was increased. The catalysts deactivation is related
to the dissolution of the metal oxides from the catalyst surface due to the acidic conditions. Phenol oxidation reaction
was strongly

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