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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
Sat Feb 09 2019
Journal Name
Journal Of The College Of Education For Women
The Impact of Polia Strategy in the Achievement and Retention of the Grammar of the Arabic Language
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ABSTRACT
Threw this research to the following:
1 - Know the impact of strategy Puglia in the collection of the rules of the Arabic language
students at the Institute of preparation parameters .
2 - Know the impact of the retention strategy in Puglia collection rules Arabic language
students at the Institute of preparation parameters .
To verify the status Mmermaa Find researcher Elsafreeten following two hypotheses :
1 - There is no statistically significant difference between the average score for the collection
of the fourth grade students at the Institute for the preparation of material parameters who
were studying grammar strategy Puglia and average grades collectible fourth grade
students at the Institu

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Publication Date
Thu Jan 16 2014
Journal Name
مجلة كلية التربية للبنات
The Impact of Polia Strategy in the Achievement and Retention of the Grammar of the Arabic Language
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Publication Date
Wed Sep 18 2019
Journal Name
Journal Of The College Of Education For Women
The Linguistic Term and the Problems of the Arabic Reception
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        The linguistic researcher reads a systematic crisis, idiomatic problems within the linguistic term coming to the Arab culture. Where most of them return back to problems of receiving these sciences which are represented by phenomena like the multiplicity linguistic term, disturbance translated idiomatic concept and its duality.

Aims of the research :

1-Initializing new textbooks to form linguistic project and Arabic linguistic theory.

2-Determination adjusted knowledge, concepts of Arabian heritage linguistics subject

3-Observation  the causes of disturbance crisis of linguistic term and its relation to

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Publication Date
Thu Feb 29 2024
Journal Name
Iraqi Journal Of Science
Monitoring the Expansion of Unplanned Urbanization and its Impact on Climate Change based on Google Earth Engine Service, a Case Study of Baghdad / Iraq
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     The earth's surface comprises different kinds of land cover, water resources, and soil, which create environmental factors for varied animals, plants, and humans. Knowing the significant effects of land cover is crucial for long-term development, climate change modeling, and preserving ecosystems. In this research, the Google Earth Engine platform and freely available Landsat imagery were used to investigate the impact of the expansion and degradation in urbanized areas, watersheds, and vegetative cover on the land surface temperature in Baghdad from 2004 to 2021. Land cover indices such as the Normalized Difference Vegetation Index, Normalized Difference Water Index, and Normalized Difference Built-up Index (NDVI, NDWI, an

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Publication Date
Wed Oct 30 2024
Journal Name
Iraqi Journal Of Science
Determining the Relationship between the Crescent Visibility Factors and the Coordinates of the Sun and Moon
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The study of the relationship between the coordinates of the sun and the moon with the crescent visibility factors has not been previously treated in a detailed and accurate way in  research and previous studies, despite its religious importance. Accordingly, this paper aims to study the relationship between the crescent visibility factors (age, lag time, elongation (ARCL), arc of vision or relative altitude (ARCV), relative azimuth (DAZ), and crescent width (W), with coordinates of the sun and the moon), and how it varies during the day of the crescent's observation. In this paper, Matlab programs were designed to calculate the ecliptic sun and moon coordinates (λ, β) and in the presence of all perturbation impacts (planets), th

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Publication Date
Thu Jun 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Use some of the scheduling rules for nursing staffs to improve operational performance _ Applied Research in al- Shahed al-Sadr General Hospital
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             Hospitals are part of the service organizations and most importantly at the level of individuals because they are tied to the people health and their daily lives , the nursing service is one of the important services provided by hospitals, and nurses are the human resource that offers this service, from this standpoint the idea of  ​​research came to prepare work Scheduling for nurses in a scientific way to improve performance operational for their services and provide efficient service available 24 hours a day, the research use one of the modern and scientific rules of scheduling its “schedule of

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Publication Date
Mon Dec 11 2017
Journal Name
Al-khwarizmi Engineering Journal
The Effects of Long-Term Operation and High Temperature on Material Properties of Austenitic Stainless Steel Type 321H
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Changes in mechanical properties of material as a result of service in different conditions can be provided by mechanical testing to assist the estimation of current internal situation of these materials, or the degree of deterioration may exist in furnaces serviced at high temperature and exceed their design life. Because of the rarity works on austenitic stainless steel material type AISI 321H, in this work, ultimate tensile strength, yield strength, elongation, hardness, and absorbed energy by impact are evaluated based on experimental data obtained from mechanical testing. Samples of tubes are extracted from furnace belong to hydrotreaterunit, also samples from un-used tube material are used to make comparisons between these properti

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Publication Date
Sun Jul 03 2022
Journal Name
International Journal Of Health Sciences
effects of toxoplasmosis infection on the levels of IL-18 and anti-ds-DNA antibodies in SLE patients
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The present study was set to demonstrate the prevalence of toxoplasmosis infection and its effects on patients with systemic  lupus erythematosus (SLE) through determining their serum levels of anti-dsDNA and IL-18 antibodies. For this purpose, the sera from 132 SLE and/or toxoplasmosis patients and 30 healthy women, were collected. The study sample was divided into four groups of SLE, toxoplasmosis, SLE coinfected with toxoplasmosis, and healthy control. Anti-Toxoplasma IgG antibodies were examined for all the samples using ELISA kit. The results showed a high mean level of anti-Toxoplasma IgG among SLE patients coinfected with toxoplasmosis (104.8792±12.31585pg/ml) in comparison to that in toxoplasmosis patients (91.1705±12.577

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Publication Date
Sun Dec 01 2013
Journal Name
Journal
The Effects Of Pbl On Understanding Of Thermodynamics, Group Work And Self-Directed Learning Skills Among Physics Undergraduates
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The aim of this study is to compare the effects of three methods: problem-based learning (PBL), PBL with lecture method, and conventional teaching on the understanding of thermodynamics, group work and self-directed learning skills among physics undergraduates. The actual sample size comprises of 122 students, who were selected randomly from the Physics Department, College of Education in Iraq, for academic year 2011-2012. In this study, the pre and posttest were done and the instruments were administered to the students for data collection. Inferential statistics were employed to analyze data. The independent variables were the PBL, the PBL with lecture method, and the conventional teaching. Dependent variables of statistical analysis were

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Publication Date
Tue Jan 01 2013
Journal Name
Iraqi Journal Of Physics
The dependence of resonant tunneling transmission coefficient on well width and barriers number of GaN/Al0.3Ga0.7N nanostructured system
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A numerical computation for determination transmission coefficient and resonant tunneling energies of multibarriers heterostructure has been investigated. Also, we have considered GaN/Al0.3Ga0.7N superlattice system to estimate the probability of resonance at specific energy values, which are less than the potential barrier height. The transmission coefficient is determined by using the transfer matrix method and accordingly the resonant energies are obtained from the T(E) relation. The effects of both well width and number of barriers (N) are observed and discussed. The numbers of resonant tunneling peaks are generally increasing and they become sharper with the increasing of N. The resonant tunneling levels are shifted inside the well by

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