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In vitro bond strengths post thermal and fatigue load cycling of sapphire brackets bonded with self-etch primer and evaluation of enamel damage
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Background: This in vitro study compares a self-etch primer (SEP) to an etch-and-rinse (EaR) for bonding sapphire brackets by evaluation of the enamel etch-pattern, shear bond strength, amount of remnant adhesive and enamel surface damage following thermal and fatigue cyclic loading. Material and Methods: Ceramic (sapphire) brackets were bonded to 80 extracted human premolars using two enamel etching protocols: conventional EaR using 37% phosphoric acid (PA) gel (control), and a SEP (Transbond Plus). Each group was subdivided into two subgroups (n=20 teeth) according to the time of bracket debonding: after 24 h water storage or following 5000 thermo-cycles plus 5000 cycles fatigue loading, to determine the shear bond strength (SBS), adhesive remnant index (ARI score), with scanning electron microscopy (SEM) evaluation of enamel condition. Results: The control subgroups consistently exhibited significantly higher (p ˂ 0.05) SBS mean values (23.4-29.8 MPa) than the SEP subgroups (15.1-22.4 MPa) at both bracket debonding time points. However, the SEP subgroups yielded milder etch-patterns and attained SBS values above the minimum requirement range for clinical performance. In addition, the higher SBS of control subgroups was accompanied with higher ARI scores and enamel damage grades than SEP subgroups as confirmed by SEM. Thermocycling and fatigue significantly reduced the SBS of all subgroups, with a non-significant drop in the amount of adhesive residue or enamel damage. Conclusions: The use of SEP can be a suitable alternative to the conventional PA gel for sapphire bracket bonding as it maintains suitable bond strength and has the potential to produce both less remnant adhesive and enamel damage

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Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Sizing and Thermal Stability of Prepared Tetraaminophthalocyaninatocopper(II) Derivatives-grafted Polymers
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Different polymers were prepared by condensation polymerization of sebacic anhydride and adipic anhydride with ethylene glycol and poly(ethylene glycol). Their number average molecular weights were determined by end group analysis. Then, they were grafted on the prepared phthalocyaninatocopper(II) compounds with the general formula (NH2)4PcCu(II) having amino groups of 3,3',3'',3'''- or 4,4',4'',4'''- positions. All prepared polymers, compounds, and phthalocyaninatocopper(II)-grafted polymers were characterized by FTIR. The sizing measurements were carried out in 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) compounds with and without grafting polymers. The results showed that the grafting process led to decreasing in par

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Publication Date
Sun Jan 01 2023
Journal Name
Computational Thermal Sciences: An International Journal
EXPERIMENTAL AND NUMERICAL ANALYSIS FOR THERMAL PROBLEM OF FRICTIONAL BRAKE SYSTEM
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The present work aims to validate the experimental results of a new test rig built from scratch to evaluate the thermal behavior of the brake system with the numerical results of the transient thermal problem. The work was divided into two parts; in the first part, a three-dimensional finite-element solution of the transient thermal problem using a new developed 3D model of the brake system for the selected vehicle is SAIPA 131, while in the second part, the experimental test rig was built to achieve the necessary tests to find the temperature distribution during the braking process of the brake system. We obtained high agreement between the results of the new test rig with the numerical results based on the developed model of the brake

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Publication Date
Wed Dec 14 2016
Journal Name
Journal Of Baghdad College Of Dentistry
Comparison of the Marginal Fitness of the Ceramic Crowns Fabricated with Different CAD/CAM Systems (An In Vitro Study)
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Background: The marginal fit is the most characteristic that closely related to the longevity or success of a restoration, which is absolutely affected by the fabrication technique. The objective of present in vitro study was to evaluate the effect of four different CAD/CAM systems on the marginal fit of lithiµm disilicate all ceramic crowns. Materials and Methods: Adentoform tooth of a right mandibular first molar was prepared to receive all ceramic crown restoration with deep chamfer finishing line (1mm) and axial reduction convergence angle of 6 degree, dentoform model duplicated to have Nickel-Chromiµm master die. Thirty two stone dies produce from master die and distributed randomly in to four groups (8 dies for each group) accor

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Publication Date
Sat Aug 01 2015
Journal Name
Journal Of Engineering
A Real-Time Fuzzy Load Flow and Contingency Analysis Based on Gaussian Distribution System
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Fuzzy logic is used to solve the load flow and contingency analysis problems, so decreasing computing time and its the best selection instead of the traditional methods. The proposed  method is very accurate with outstanding computation time, which made the fuzzy load flow (FLF) suitable for real time application for small- as well as large-scale power systems. In addition that, the FLF efficiently able to solve load flow problem of ill-conditioned power systems and contingency analysis. The FLF method using Gaussian membership function requires less number of iterations and less computing time than that required in the FLF method using triangular membership function. Using sparsity technique for the input Ybus sparse matrix data gi

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Publication Date
Sat Aug 21 2021
Journal Name
Engineering, Technology & Applied Science Research
A Comparison between Static and Repeated Load Test to Predict Asphalt Concrete Rut Depth
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Rutting has a significant impact on the pavements' performance. Rutting depth is often used as a parameter to assess the quality of pavements. The Asphalt Institute (AI) design method prescribes a maximum allowable rutting depth of 13mm, whereas the AASHTO design method stipulates a critical serviceability index of 2.5 which is equivalent to an average rutting depth of 15mm. In this research, static and repeated compression tests were performed to evaluate the permanent strain based on (1) the relationship between mix properties (asphalt content and type), and (2) testing temperature. The results indicated that the accumulated plastic strain was higher during the repeated load test than that during the static load tests. Notably, temperatur

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Publication Date
Fri May 01 2015
Journal Name
Journal Of Engineering
Cooling Load Calculations For Typical Iraqi Roof And Wall Constructions Using Ashrae's RTS Method
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The present work is an attempt to develop design data for an Iraqi roof and wall constructions using the latest ASHRAE Radiant Time Series (RTS) cooling load calculation method. The work involves calculation of cooling load theoretically by introducing the design data for Iraq, and verifies the results experimentally by field measurements. Technical specifications of Iraqi construction materials are used to derive the conduction time factors that needed in RTS method calculations. Special software published by Oklahoma state university is used to extract the conduction factors according to the technical specifications of Iraqi construction materials.  Good agreement between the average theoretical and measured cooli

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Publication Date
Tue Jan 01 2019
Journal Name
Journal Of The College Of Languages (jcl)
Self-rhythm of the Belenoby Poet
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Al- belenoby , Andalusian obscure poet .I choose to study poetic rhythm in this poetic and the appropriateness of with what  rhythm touring in his self to give beautiful meaning raise to receiver to put the hands of continental placements creativity in poetry .I divided my research into ideas are presented in a sequential manner , I started researching with poetic rhyme than rhyme they represent the form of the poem, they represent the external form of the poem and their music that farm the general concept then the rhetorical styles that represent the internal form of the poem and it music that the listener works and enjoying it part by part all this led to the put the hands of the receiver placement creativity in Belenoby Poet.&nbs

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
The Possible Self of University Students
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The current research aims to identify the possible self of university students and the differences in the level of possible self of students in terms of gender, specialization (scientific-humanitarian), and the interaction between them. In order to achieve the objectives of the current research, the two researchers have prepared a scale of the possible self, based on the theory (Markus and Nurius, 1986). The research tool was applied to a sample of (400) male and female students who were selected through a random stratified method from Al-Mustansiriya University students/morning studies for the academic year (2019-2020). The researcher reached the following results: the research sample has a high level of possible self; there is a differ

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Publication Date
Mon Apr 04 2022
Journal Name
Journal Of Educational And Psychological Researches
The Vocational Self of Educational Counselors
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The current research aims to identify the Vocational Self of the educational counselors as well as to identify the significant difference in the professional self according to the gender variable (male-female). The researcher adopted the scale of al-hasani (2015), which consisted of (34) items. It was applied to a sample of (300) school counselors (male-female) who were randomly selected from the six directorates in the Baghdad governorate for the academic year 2020/2021. The results showed that the research sample of educational counselors has a vocational self-concept. There are no statistically significant differences in the vocational self-concept between males and females among the educational counselors.

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Publication Date
Mon Jul 31 2017
Journal Name
Journal Of Engineering
Experimental and Numerical Investigation of Hyper Composite Plate Structure Under Thermal and Mechanical Loadings
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