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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 Jan 01 2013
Journal Name
Iraqi Journal Of Physics
Describing the Wavefront Aberrations of the Hexagonal Aperture Using Modified Zernike Polynomials
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n Segmented Optical Telescope (NGST) with hexagonal segment of spherical primary mirror can provide a 3 arc minutes field of view. Extremely Large Telescopes (ELT) in the 100m dimension would have such unprecedented scientific effectiveness that their construction would constitute a milestone comparable to that of the invention of the telescope itself and provide a truly revolutionary insight into the universe. The scientific case and the conceptual feasibility of giant filled aperture telescopes was our interested. Investigating the requirements of these imply for possible technical options in the case of a 100m telescope. For this telescope the considerable interest is the correction of the optical aberrations for the coming wavefront, th

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Publication Date
Fri May 15 2009
Journal Name
Journal Of Planner And Development
ENHANCEMENT OF THE SOCIAL DIMENSION IN THE SUSTAINABLE ENVIRONMENT STRATEGY IN IRAQ
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Improving the environment is a mission that should be conducted by three associates; public authorities, environmentalists and the community. The ignorance of environmental education in Iraq has resulted to an almost environmentally illiterate community, demanding well planned programs to raise their environmental; awareness and education. On the other hand, the decision makers should be well informed about the citizens' environmental preferences to be able to set their priorities for the civil services. Merging the Iraqi citizens in listing their environmental priorities is one of many other approaches for "Environment Education" programs. Globally, such methods have proven to be effective and resulted to widespread understandin

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Publication Date
Wed Mar 30 2022
Journal Name
Journal Of Educational And Psychological Researches
University Strategic Planning Necessary to Invest the Outputs of the Distinguished Schools
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The seventh international scientific conference held at the "University of Baghdad" College of Education "Ibn Rushd" 14-15 / 4/2019, confirmed in its recommendations the need to draw clear strategic planning to invest the qualitative inputs from the Ministry of Education and focus on it in higher education, which requires educational institutions to amend from its current strategies or adopting new strategies in a way that contributes to presenting new ways to compete and keep pace with scientific progress and to find realistic and objective working methods. The aim of the current study is to identify the reality of university strategic planning to invest the outputs of the distinguished schools of the heads of public universities. The r

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Publication Date
Fri Mar 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Some indicators of the economic productivity in the industrial sector in Iraq
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Industry represents a cornerstone of the process of economic development and a measure of progress and contribute to increased prosperity and high standard of living.

The researcher analyzed the productivity indicators in industrial facilities large and small at several time periods ranging from 1970 to 2009, according to the economic situation that prevailed in each period.

    Different impact of periods under discussion, it made ​​Iraq the cash surpluses during the period 70-1980 then the effects of the war after 1980 and the economic blockade since 1990, and the subsequent events of the year

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Publication Date
Tue Jul 15 2025
Journal Name
Smart Innovation, Systems And Technologies
The Role of the European Economic Security Strategy in Managing Economic Risks
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Publication Date
Fri Jul 01 2016
Journal Name
Al–bahith Al–a'alami
The Discourse of the Absent Woman Novel for Mahdi Issa Al-Saqr
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The semiotic trend of recent monetary trends task that took a wide range of attention of critics and readers alike, especially after the deployment, which accompanied him after widespread acts critic Grimas and powers applicable to the literary texts and is thus expanded its care circle, hence the choice of the novel (absent) woman Iraqi novelist (Mahdi ‘Issa falcon) model to be applied to the study chose to be a semiotic approach through the use of procedural mechanisms for its critical tool (Paris School of semiotics), cash and views of its founder critic Grimas.The research in the introduction and pave came we made it a vision for literary semiotic and its impact trend in cash and cash is and what it desire to clarify some poked suc

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Publication Date
Tue Jun 14 2016
Journal Name
Al-academy
Space Treatment in the Ceramic Sculpture of the Potter "Shinyar Abdua – Allah"
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Space is considered as an important element in constructing artwork, it can be a dominant and fulfilled part that adds new existence to the content. Each artwork must have a space artistically or analytically. The internal and eternal space of artwork have associated with each other in order to be ann important connected unit that establishes the work epressions and helps the audience to understand it. Such kind of works can be represented by the works of the potter (Sheinyor Abdu Allah) which have uarious expressions of space which this study is based on.The study aims at finding out the treatment of apace in the ceramic sculpture works of the potter (Sheinyar Abdu Allah).The second chapter has many sections. T

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Publication Date
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
BUMPINESS IN THE ATMOSPHERE IN IRAQ STUDY IN THE GEOGRAPHY OF CLIMATE
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Bumpiness in the atmosphere is the vertical movement of air, whether
upward or downward movement and the bumpiness is accompanied by areas
of unrest in the air and wind. And contribute to each of the coups thermal
fronts, wind, wind and thunderstorms. Moreover, bumpiness is net of the
reasons that lead to circumstances is appropriate to cut the wind, and this
contributes to the formation of bumpiness in the atmosphere. The study found
that the noon of the times, which is expected to occur where clear-air
bumpiness during flights because of the warmth of the earth's surface. The
study found increased incidence of air hole during the summer, especially
July, due to increased incidence of coup surface, while the s

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Publication Date
Thu Oct 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
The role of moral values in the tourism service ,An analytical study
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Business Ethics play a major role in explaining the behavior of those interested in the management of tourism enterprises in the field of management gains, which sometimes turn to manipulation in the specification of the service of tourism and influence in the technical characteristics at the expense of the brand and market share, as well as misleading beneficiaries about the fact that the performance of the service of tourism, may depend activities tourist dramatically when submitting and sharing various services on the types of mutual relations the framework for moral distinct, in interaction or direct contact between producers of tourism services and tourists or their beneficiaries, in order to provide comfort and recreation a

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Crossref
Publication Date
Sun Apr 01 2018
Journal Name
Al–bahith Al–a'alami
The uses used in the political implications of Arabic-speaking foreign website
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This research is intended to high light the uses of political content in foreign Arabic / speaking websites, such as “ CNN “ and” Euro News“, The research problem stems from the main question: What is the nature of the use of the websites in the political content provided through them? A set of sub-questions that give the research aspects and aims to achieve a set of objectives , including the identification of topics that included , the political content provided through , the sample sites during the time period for analysis and determine that the study uses descriptive research based on the discovery of the researcher, describing it accurately and defining the relations between the components.
The research conducted the des

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