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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
Wed Jan 26 2022
Journal Name
Iraqi Journal Of Science
Potentiometric Determination of Mebeverine Hydrochloride Using Imprinted Molecular Polymer in PVC Matrix Membrane‏
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Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Estimate missing value by use analyses of covariance method for split block-design
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The research aims to estimate missing values using covariance analysis method Coons way to the variable response or dependent variable that represents the main character studied in a type of multi-factor designs experiments called split block-design (SBED) so as to increase the accuracy of the analysis results and the accuracy of statistical tests based on this type of designs. as it was noted in the theoretical aspect to the design of dissident sectors and statistical analysis have to analyze the variation in the experience of experiment )SBED) and the use of covariance way coons analysis according to two methods to estimate the missing value, either in the practical side of it has been implemented field experiment wheat crop in

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Publication Date
Thu Jun 27 2019
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
BIODIVERSITY STUDY OF ZOOPLANKTON IN SELECTED BAHR Al-NAJAF DEPRESSION, NAJAF GOVERNORATE, IRAQ
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The current study aims to assess zooplankton diversity in Bahr Al-Najaf depression using diversity index, specimens were collected from five sites at Bahr Al-Najaf depression, Iraq during April 2017 to March 2018.

 

Forty-eight taxa of zooplankton were identified including 26 taxa to Copepoda, 17 taxa belonged to Rotifers and 5 taxa to Cladocera: Copepoda was the most dominant group (54.2%); Rotifera comprised (35.4%); Cladocera comprised (10.4%).

 

Relative abundance index of zooplankton showed Copepodite and nauplii of Harpacticoid, Hexarthra mira, Daphnia sp., Harpacticoid sp., and Copepodite and nauplii of Cyclops were more abundant. According to the constancy index

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Publication Date
Sat Nov 30 2024
Journal Name
Iraqi Journal Of Science
Admissible Classes of Seven-Parameter Mittag-Leffler Operatorwith Third-Order Differential Subordination Properties
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The main purpose of this paper, is to characterize new admissible classes of linear operator in terms of seven-parameter Mittag-Leffler function, and discuss sufficient conditions in order to achieve certain third-order differential subordination and superordination results. In addition, some linked sandwich theorems involving these classes had been obtained.  

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Publication Date
Fri May 31 2019
Journal Name
Journal Of Engineering
A Comparative Study of Various Intelligent Algorithms based Path Planning for Mobile Robots
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In general, path-planning problem is one of most important task in the field of robotics. This paper describes the path-planning problem of mobile robot based on various metaheuristic algorithms. The suitable collision free path of a robot must satisfies certain optimization criteria such as feasibility, minimum path length, safety and smoothness and so on. In this research, various three approaches namely, PSO, Firefly and proposed hybrid FFCPSO are applied in static, known environment to solve the global path-planning problem in three cases. The first case used single mobile robot, the second case used three independent mobile robots and the third case applied three follow up mobile robot.  Simulation results, whi

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Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Engineering
Design of a PID-Lead Compensator for a Twin Rotor Aerodynamic System (TRAS)
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This paper deals with a Twin Rotor Aerodynamic System (TRAS). It is a Multi-Input Multi-Output (MIMO) system with high crosscoupling between its two channels. It proposes a hybrid design procedure that combines frequency response and root locus approaches. The proposed controller is designated as PID-Lead Compensator (PIDLC); the PID controller was designed in previous work using frequency response design specifications, while the lead compensator is proposed in this paper and is designed using the root locus method. A general explicit formula for angle computations in any of the four quadrants is also given. The lead compensator is designed by shifting the dominant closed-loop poles slightly to the left in the

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Publication Date
Tue Oct 05 2010
Journal Name
Journal Of College Of Education For Women
Conversation Analysis of Forum: a Selected Text from Paul S. Kemp Online Journal
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Language as a means of communication has long been the concern of many conversation analysts in their studies such as: Sacks et al. (1974), Schegloff et al. (1977), Duncan (1972), Grice (1975) and Burton (1980). Burton has attempted analyzing the first ten transitions of the play “The Dumb Waiter” for mere a presentation of her approach. This paper aims at analyzing the conversational structure of forum on the subject of literary fiction and genre fiction by applying Burton’s model (1980) of analysis to answer the question to what extent this model is applicable in analyzing the presented text. The findings of the investigation have proved the applicability of the structure of conversation formulated by Burton (1980) in her model wit

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Publication Date
Sun Feb 10 2019
Journal Name
Iraqi National Journal Of Nursing Specialties
Evaluation of Nurses’ Practices toward Safe Intravenous Chemotherapy Infusion in Baghdad City Hospitals
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Abstract Objectives: The study aims to evaluate the nurses' practices that concerning intravenous chemotherapy infusion and to find out the association between nurses' practices and their level of education, year of experiences, and training course.
Methodology: A descriptive study was conducted in Baghdad Teaching Hospital and Al Amal National Hospital for Treatment of Tumors for the purpose of evaluating the practices of nurses related to infusion of intravenous chemotherapy for the period from 20th October 2017 to 14th March 2018. The sample was randomly selected from both hospitals. Who were evaluated by using a checklist to observe their practices which consisted of two parts; the first part included the demographic information

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Publication Date
Sun Dec 17 2017
Journal Name
Al-khwarizmi Engineering Journal
Experimental Simulation of Natural Heat Convection from Finned Vertical Plate with Different Inclinations
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In this work an experimental simulation is made to predict the performance of steady-state natural heat convection along heated finned vertical base plate to ambient air with different inclination angles and configurations of fin array. Two types of fin arrays namely vertical fins array and V-fins array on heated vertical base plate are used with different heights and spaces. The influence of inclination angle of the plate , configuration of fins array and fin geometrical parameters such as fin height and fin spacing on the temperature distribution, base convection heat transfer coefficient and average Nusselt number have been plotted and discussed. The experimental data are correlated to a formula between average Nusselt number versus R

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Publication Date
Wed Dec 01 2010
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
HELMINTH PARASITIC FAUNA OF AQUATIC BIRDS IN BAHR AL-NAJAF DEPRESSION, MID IRAQ
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For two years, from January 1995 till December 1996, a survey on helminth parasites of aquatic birds of Bahr Al-Najaf depression, mid Iraq, was achieved. A total of 663 birds, belonging to 11 species, were captured and examined for helminth parasites. These birds were infected with seven trematodes (Notocotylus gibbus, Cyclocoelum mutabile, Echinostoma chloropodis, Patagifer parvispinosus, Psilochasmus oxyurus, Diplostomum spathaceum and Apharyngostrigea cornu), seven cestodes (Paricterotaenia porosa, Dicranotaenia tsengi, Diorchis brevis, D. inflatus, Tatria acanthorhyncha, T. decacantha and Diplophallus polymorphus) and four nematodes (Capillaria sp., Eustrongylides tubifex, Con

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