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The effect of composite bonding spot size and location on the performance of poly-ether-ether-ketone (PEEK) retainer wires
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Background: Poly-ether-ether-ketone(PEEK) has been introduced to many dental fields. Recently it was tested as a retainer wire‎ following orthodontic treatment. This study aimed to investigate the effect of changing the bonding spot size and location on the performance of PEEK retainer wires. Methods: A biomechanical study involving four three-dimensional finite element models was performed. The basic model was with a 0.8 mm cylindrical cross-section PEEK wire, bonded at the center of the lingual surface of the mandibular incisors with 4 mm in diameter composite spots. Two other models were designed with 3 mm and 5 mm composite sizes. The last model was created with the composite bonding spot of the canine away from the center of the crown, closer to the lateral incisor. The linear displacement of the teeth, strains of the periodontal ligament, and stresses in PEEK wire and composite were evaluated. The data was numerically produced with color coded display by the software. Selected values were tabulated and compared among models. Results: The amount of linear displacement and strain was very low. Stresses in the wire and composite were affected by the size and position of the composite bonding spot. The safe limits were identified at 235 MPa for PEEK and 100 MPa for composite. The basic model had a von Mises stress in the PEEK wire of 122.09 MPa, and a maximum principal stress in the composite of 99.779 MPa. Both stresses were within the safe limits, which means a lower risk of failure in PEEK and composite. All other models had stresses that exceeded the safe limit of the composite. The 3 mm composite model was the only one that developed stresses in the wire more than the safe limits of PEEK. Conclusions: Within the limitations of this study, bonding PEEK wires with 4 mm bonding spots to the clinical crown center provided the best mechanical performance of the wires and spots; otherwise, the mechanical properties of the wire and composite would be affected and, therefore, might affect the retention process. Keywords: Retention, PEEK, Finite element analysis

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Publication Date
Fri Jul 28 2023
Journal Name
Journal Of Optics
Estimated the nanoparticles size of CdS from UV–Vis spectrum absorption by effective mass approximation model (EMA) using capping and complex agent
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Publication Date
Sun Feb 28 2021
Journal Name
Journal Of Economics And Administrative Sciences
The effect of increasing the volume of debt on the volume of trading (applied research on a sample of private banks listed on the Iraq Stock Exchange)
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This research worked on identifying the effect of increasing the volume of indebtedness by companies listed on the Iraq Stock Exchange on the trading volume of those companies, and this research included some theoretical concepts related to both debt financing and trading volume, and it represents the research community of the joint-stock companies listed in The Iraq Stock Exchange (the banking sector). As for the research sample, it was deliberately chosen represented by companies with continuous trading without stopping, which reached 10 joint-stock companies, and the period of research was extended during the period 2011-2015, and a set of indicators and financial methods were used In measuring research v

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Publication Date
Tue Oct 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Effect of irrigation type and method on the cost of producing dunum of wheat crop
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Abstract :  This research is concerned with studying the best type and method of  irrigation as well as the best cultivated area to reduce the cost of producing  dunums of wheat crop in Iraq , and was based on data taken from the Ministry of Planning / Central Statistical Organization About cost of wheat crop production for (12) Iraqi governorates except Kurdistan, Nineveh, Salah al-Din, Anbar) and the sample size (554) according to the cost survey carried out by the Ministry of Planning / Central Statistical Organization for 2017, The results of the research showed that there are significant statistical differences between production costs when using t

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Publication Date
Sat Jan 01 2022
Journal Name
Journal Of Ovonic Research
Effect of dopant of aluminum on the structural and optical properties of NiTsPc thin films
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Publication Date
Fri Sep 09 2022
Journal Name
Journal Of Ovonic Research
Effect of dopant of aluminum on the structural and optical properties of NiTsPc thin films
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The (NiTsPc) thin films operating by vacuum evaporation technique are high recital and good desirable for number of applications, were dumped on glass substrates at room temperature with (200±20nm) thickness and doped with Al at different percentage (0.01,0.03) besides annealing the sample with 200˚C for 1 hours . The stimuluses of aluminum dopant percentage on characterization of the dropped (Ni Ts Pc) thin films were studied through X-ray diffraction in addition from the attained results, were all the films have polycrystalline in nature, as well the fallouts of XRD aimed at film illustrations polycrystalline, depending on the Al ratio doping, the results, SEM exposed the surface is regularly homogeneous. Utilizing first-ideolog

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Publication Date
Wed Apr 10 2013
Journal Name
Journal Of The College Of Basic Education
Effect of heavy metal ions copper, cadmium and cobalt on the growth and reproduction of the aquatic fungus Saprolegnia hypogyna.
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The current study aimed to evaluate the effect of the heavy metals copper, cadmium and cobalt when added individually, in combination and in combination on the growth and reproduction of the aquatic fungus Saprolegnia hypogyna.

Publication Date
Thu Jun 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Controller work specificity and their impact on performance (Applied Study in the financial oversight bodies)
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The research aims to a statement of specificity of the Controller of (academic achievement, specialty, job title, length of service, Gender) and its impact on performance, Through a proposed appraisal form includes three main axes and each axis including several specialized elements in the supervisory work in form (check list). as is the importance of research to enable officials of oversight bodies financial identify and diagnose performance Controller through what has this observer of the process of scientific properties when performing supervisory work. Be summarized problem of the research that the lack of regulatory institution with the Controller interesting in terms of the necessary characteristics and requirements and inv

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Publication Date
Sat Dec 30 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Studying the Connection Between Partical Size and Lattice Distortions Through X - Ray Diffraction Line Profile Analysis for CaO Powder
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The integral  breadth  method  has been utilized to analyse line

proIiles broadening and lattice strain of CaO at different temperatures

The effect of tcmperattre on crystallite size and strain has also been investigated  . The crystall i tes are found to be highly anisotropic even at high temperatures

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Publication Date
Mon Nov 09 2015
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
The effect of different thermal treatments and pH on the stability of a glycyrrhizin which Product from the licorice plant, Glycyrrhiza glabra L: The effect of different thermal treatments and pH on the stability of a glycyrrhizin which Product from the licorice plant, Glycyrrhiza glabra L
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The plant licorice is considered important plants as nutritionally and medically and economically, as a rich in phytochemical, vitamins and minerals, and being widely available, Research indicated the presence of many nutrients such as (proteins, Carbohydrates, vitamins and minerals) as well as presence of Glycyrrhizin which responsible of sweet taste, that allowing the possibility to use it as natural intensity sweetener with few calories in Sweetening of many food. This research is aimed to study the Stability of Glycyrrhizin toward the various manufacturing conditions such as (thermal treatment, pH of foods and microwaves), so three factorial experiments was implemented to find out the Stability as following: 100C° - 121C° - Microwa

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Publication Date
Wed Mar 08 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Effect of Temperature and Nickel Concentration on the Electrical and Dielectric Properties of Polyethylene-Nickel Composites
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The effect of temperature range from 298 K to 348 K and volume filler content ф on electrical properties of polyethylene PE filled with nickel Ni powders has been investigated. The volume electrical resistivity V  of such composites decreases suddenly by several orders of magnitude at a critical volume concentration (i.e. фc=14.27 Vol.%) ,whereas the dielectric constant   and the A.C electrical conductivity AC  of such composites increase suddenly at a critical volume concentration (i.e. фc=14.27 Vol.%).For volume filler content lower than percolation threshold ф<фc the resistivity decreases with increasing temperature, whereas the dielectric constant and the A.C electrical conductivity of

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