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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
Mon May 01 2023
Journal Name
International Journal Of Supply And Operations Management
How has covid-19 affected the logistics of Europe, Asia and Africa, and do appropriate solutions differ between countries?
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Publication Date
Wed Jun 01 2022
Journal Name
Iraqi Journal Of Veterinary Sciences
Histological and histochemical observations of the prostate gland at resting and stimulating status in adult local Dog (Canis familiaris)
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Publication Date
Sat Feb 26 2022
Journal Name
Iraqi Journal Of Science
2D Seismic Data Reinterpretation and The Structural View of Zubair, Yamama, and Gotnia Formations in Afaq Area, Central Iraq
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     An interpretative study of the two-dimensional seismic data of the Afaq area was conducted using the Petrel 2017 software. 2D seismic reflection sections are used to give a structural interpretation of Afaq structure based on synthetic seismogram and well log data. Three reflectors, Zubair, Yamama, and Gotina Formations, were selected. These reflectors are defined from well west kifl (wk-1), Where located adjacent to the study area. Structural maps of the Zubair, Yamama, and Gotnia formations are prepared and interpreted, including TWT maps, Average velocity maps, and depth maps. The studies concluded that the Afaq structure area does not contain main faults, but secondary faults with short and limited extensions

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Publication Date
Tue Feb 14 2023
Journal Name
Journal Of Educational And Psychological Researches
Partnership between Secondary Schools and Community Agencies to Improve the Outcomes of Students with Intellectual Disabilities (Reality and Development)
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Abstract

The current research aims to identify the level of partnership between school and community agencies to improve secondary school outcomes for students with intellectual disabilities and develop strategies that help enhance community partnerships between schools and agencies. The researcher used the qualitative research approach; he utilized the interviews as a tool for data collection. The sample of research included (12) participants: three female school leaders, three male-school leaders, three female-school supervisors, and three male-school supervisors in schools that have programs for students with intellectual disabilities in Riyadh. The results of the study showed that the level of partnership bet

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Publication Date
Sun Sep 29 2019
Journal Name
Iraqi Journal Of Science
The Competition between of invasive Hydrilla verticillata L.f. and native Ceratophyllum demersum L. in monocultures and mixed cultures experimental
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     The present study aims to assess inter-specific competition between Hydrilla verticillata and Ceratophyllum demersum. A competition experiment design has five treatment combinations to terminal shoots of C. demersum only, terminal shoots of H. verticillata only and three different treatment combinations of C. demersum and H. verticillata together. Our results showed parameters growth of C. demersum were decreased of which, total chlorophyll, protein, and biomass while Superoxide dismutase (SOD), and Catalase (CAT) enzymes increase were significantly (p<0.05) compare with control treatment. While H. verticillata were increased total chlorop

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Publication Date
Sun Feb 03 2019
Journal Name
Iraqi Journal Of Physics
Study of Doppler broadening Compton scattering and cross section determination for the elements Fe, Zn, Ag, Au and Hg
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To assess the contribution of Doppler broadening and examine the
Compton profile, the Compton energy absorption cross sections are
measured and calculated using formulas based on a relativistic
impulse approximation. The Compton energy-absorption cross
sections are evaluated for different elements (Fe, Zn, Ag, Au and Hg)
and for a photon energy range (1 - 100 keV). With using these crosssections,
the Compton component of the mass–energy absorption
coefficient was derived, where the electron momentum prior to the
scattering event caused a Doppler broadening of the Compton line.
Also, the momentum resolution function was evaluated in terms of
incident and scattered photon energy and scattering angle. The res

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Publication Date
Sun Aug 01 2021
Journal Name
Biochemical & Cellular Archives,
ANTIMICROBIAL ACTIVITY OF CHITOSAN AND/OR GUM ARABIC IN THE LOCAL PRODUCE SOFT AND HARD CHEESE IN BAGHDAD CITY
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antimicrobial solutions against Coliforms, E. coli O157: H7, yeasts and molds were evaluated by agar well diffusion method. Chitosan (CH) exhibited best antimicrobial activity against the treated microorganisms at concentration of (5%) with contact time for 6hrs at refrigeration temperature (4ÚC), zones of inhibition for (GA) and (CH) for each solution alone ranging from (0 to 10 mm), chitosan solution (CH) exhibited both antibacterial and antifungal activities, Gum Arabic washing solution showed significant antibacterial activity (P < 0.05) against the microorganisms at concentration (15%), without inhibitory effect against E. coli O157:H7 at concentration (10%), in the current study the results confirmed that (15%) (w/v) of GA and 5%

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Publication Date
Fri Dec 06 2019
Journal Name
Ssociation Of Arab Universities Journal Of Engineering Sciences
Application of Artificial Neural Network and GeographicalInformation System Models to Predict and Evaluate the Quality ofDiyala River Water, Iraq
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This research discusses application Artificial Neural Network (ANN) and Geographical InformationSystem (GIS) models on water quality of Diyala River using Water Quality Index (WQI). Fourteen water parameterswere used for estimating WQI: pH, Temperature, Dissolved Oxygen, Orthophosphate, Nitrate, Calcium, Magnesium,Total Hardness, Sodium, Sulphate, Chloride, Total Dissolved Solids, Electrical Conductivity and Total Alkalinity.These parameters were provided from the Water Resources Ministryfrom seven stations along the river for the period2011 to 2016. The results of WQI analysis revealed that Diyala River is good to poor at the north of Diyala provincewhile it is poor to very polluted at the south of Baghdad City. The selected parameters wer

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Publication Date
Sun Apr 30 2023
Journal Name
Iraqi Geological Journal
Depositional and Sratigraphic Evolution of the Early-Middle Miocene Succession in Hamrin, Ajeel and Mansuriyha Oil Fields, Central Iraq
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The Early-Middle Miocene succession in Iraq is represented by the Serikagni, Euphrates and Dhiban formations, which deposited during the Early Miocene. The Jeribe and Fatha successions were deposited during Middle Miocene age. This study includes microfacies analysis, depositional environments, sequence stratigraphy and basin development of Early – middle Miocene in Hamrin and Ajeel oil fields and Mansuriyha Gas Field. The study area includes four boreholes in three oil fields located in central Iraq: Hamrin (Hr-2) and Ajeel (Aj-13, and 19) oil feilds, and Mansuriyha (Ms-2) Gas Field. Five facies associations were distinguished within the studied fields: deep marine, slop, platform-margin, open marine, restricted interior platform

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Publication Date
Mon Feb 01 2021
Journal Name
Meta Gene
Association analysis of FTO gene polymorphisms rs9939609 and obesity risk among the adults: A systematic review and meta-analysis
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