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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
Tue Apr 08 2025
Journal Name
Heat Transfer
Experimental Study on the Performance of Gradient Pores Density Metal Foam in a Rectangular Channel
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ABSTRACT<p>Various approaches are employed to enhance the heat transfer coefficient and Nusselt number inside the channels. One of the techniques employed for these enhancements is the utilization of porous media. In the current article, a practical investigation of forced convection heat transfer in a rectangular cross‐section channel (0.05 × 0.1 m<sup>2</sup>) with 0.25 m length is conducted. A heater with a heat flux range (450–6000 W/m<sup>2</sup>) is imposed under a copper plate, and the other sides are covered by insulation layers. The air is considered as a working fluid with <italic>Re</italic> (600–2100). The test section is fully filled with gradient pore</p> ... Show More
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Publication Date
Wed May 02 2012
Journal Name
Journal Of Planner And Development
The Effect of Time and Place Dimensions on Changing the Quality Dimensions of Sizes of Cities: A Case Study (Baghdad city)
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The city has normal natural state, and the man has a usual movement, change and search for the new .Also, the city has a usual change and transform in its time, place and quality (sizes)structures. The city has a solid memory diving into the past and the future and reflects The real present, and this memory has a timing layers change into real materialistic place making the city has accumulated overlapping circles which is hard to break u , and it broadcasts the lockup timing density ,in which there is no visual record precisely, it is just like((the social record)) that evaluates the un visual relationships between the components and parts of the city (community and form) in a visual quiet exhibition and transform change inside.

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Publication Date
Wed Dec 30 2009
Journal Name
Iraqi Journal Of Physics
Study the Effect of annealing temperature on the Structure of a-Se and Electrical Properties of a-Se/c-Si Heterojunction
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In this work Study effect of annealing temperature on the Structure
of a-Se and electrical properties of a-Se/c-Si hetrojunction have been
studied.The hetrojunction fabricated by deposition of a-Se film on c-
Si using thermal evaporation.
Electrical properties of a-Se/ c-Si heterojunction include I-V
characteristics, in dark at different annealing temperature and C-V
characteristics are considered in the present work.
C-V characteristics suggested that the fabricated diode was
abrupt type, built in potential determined by extrapolation from
1/C2-V curve. The built - in potential (Vbi) for the Se/ Si System
was found to be increase from 1.21 to 1.62eV with increasing of
annealing temperature

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Publication Date
Sat Jul 28 2018
Journal Name
Journal Of Engineering
Evaluation Microstructure and the Mechanical Properties of Composite Material for Al-Matrix Reinforced by Ceramic Materials (Sic And Al2O3)
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In this investigation, the mechanical properties and microstructure of Metal Matrix Composites (MMCs) of Al.6061 alloy reinforced by ceramic materials SiC and Al2O3 with different additive percentages 2.5, 5, 7.5, and 10 wt.% for the particle size of 53 µm are studied. Metal matrix composites were prepared by stir casting using vortex technique and then treated thermally by solution heat treatment at 530 0C for 1 hr. and followed by aging at 175 0C with different periods. Mechanical tests were done for the samples before and after heat treatment, such as impact test, hardness test, and tensile test. Also, the microstructure of the metal matrix composites was examine

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Publication Date
Sun Oct 11 2026
Journal Name
Retos: Nuevas Tendencias En Educación Física, Deporte Y Recreación, Issn-e 1988-2041, Issn 1579-1726, Nº. 70, 2025, Págs. 1438-1445
The effect of a nutritional program on the electromyography (EMG) of some muscles of weightlifters in the snatch lift
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Autorías: Omar Khalid Yasir, Marwa Husein Ali, Aws Miqdad Jafar Hassan Alhusseini. Localización: Retos: nuevas tendencias en educación física, deporte y recreación. Nº. 70, 2025. Artículo de Revista en Dialnet.

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Publication Date
Wed May 01 2024
Journal Name
Journal Of Physics: Conference Series
Study of The Effect of Concentration on The Efficiency of The Sensitive N749-TiO<sub>2</sub> Solar Cell
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Abstract<p>In this research, we studied the effect of concentration carriers on the efficiency of the N749-TiO<sub>2</sub> heterogeneous solar cell based on quantum electron transfer theory using a donor-acceptor scenario. The photoelectric properties of the N749-TiO<sub>2</sub> interfaces in dye sensitized solar cells DSSCs are calculated using the J-V curves. For the (CH3)3COH solvent, the N749-TiO<sub>2</sub> heterogeneous solar cell shows that the concentration carrier together with the strength coupling are the main factors affecting the current density, fill factor and efficiency. The current density and current increase as the concentration increases and the </p> ... Show More
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Publication Date
Sat Jul 01 2023
Journal Name
Journal Of Engineering
Using of Constructed Wetlands in The Treatment of Wastewater: A Review for Operation and Performance: Review for Using of Constructed Wetlands in The Treatment of Wastewater: Operation and Performance
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Wastewater recycling for non-potable uses has gained significant attention to mitigate the high pressure on freshwater resources. This requires using a sustainable technique to treat natural municipal wastewater as an alternative to conventional methods, especially in arid and semi-arid rural areas. One of the promising techniques applied to satisfy the objective of wastewater reuse is the constructed wetlands (CWs) which have been used extensively in most countries worldwide through the last decades. The present study introduces a significant review of the definition, classification, and components of CWs, identifying the mechanisms controlling the removal process within such units. Vertical, horizontal, and hybrid CWs

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Publication Date
Sat Sep 30 2023
Journal Name
Modern Sport
The effect of Tabata exercises on the development of stamina and achievement for female athletes running 100m hurdles under the age of 18 years
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يعد علم التدريب الرياضي الحديث عملية تربوية علمية مبنية على اسس صحيحة هدفها وصول اللاعبين الى التكامل في الاداء الفني وهذا يتم عن طريق التأثير المنظم والدقيق بواسطة استعمال التمارين البدنية التي تحدث تغيرات خاصة في عمل اعضاء واجهزة جسم الرياضي والتي بدورها تؤدي الى رفع كفاءة الاعضاء والاجهزة لتحقيق الانجازات الرياضية العالية ولقد استعملت الباحثتان اسلوب حديث من اساليب التدريب الرياضي من اجل تطوير تحم

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Publication Date
Sun Oct 02 2016
Journal Name
Journal Of Educational And Psychological Researches
The Effect Of Flexible Grouping Strategy And Three Step Interview Strategy On Achievement Of The History Material Among Student Of The First Intermediate Class
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  The research aims to know The Effect Of Flexible Grouping Strategy  and Three Step Interview strategy on achievement of the history material among student of the first literary class, The Researcher used the experimental design of the two experimental groups and the control group and with post test, researcher group (a) represent the experimental group taught according the Flexible Grouping Strategy  , and Division (c) to represent the second experimental group which studied according Three Step Interview strategy and Division (b ) to represent the control group taught in the traditional method, the number of students (99) students of (33) female students in each division. T

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Publication Date
Tue Jan 01 2019
Journal Name
Energy Procedia
Studying The Effect of The Type of Substrate on The Structural, Morphology and Optical Properties of TiO2 Thin Films Prepared by RF Magnetron Sputtering
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