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Effect of Artificial Aging Test on PEEK CAD/CAM Fabricated Orthodontic Fixed Lingual Retainer
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Background: The purpose of this study was to evaluate the effect of in vitro long-term simulation of oral conditions on the bond strength of PEEK CAD/CAM lingual retainers.

Material and methods: The sample consisted of 12 PEEK CAD/CAM retainers each composed of 2 centrally perforated 3x4mm pads joined by a connector. They were treated by 98% sulfuric acid for 1 minute and then conditioned with Single Bond Universal and bonded to the lingual surface of premolar teeth by 3M Transbond TM System. Half of the retainers were artificially aged using a 30-day water storage and 5000 thermocycling protocol before bond strength testing to compare with the non-aged specimens.

Results: The artificially aged retainers showed a marginally lower bond strength than the non-aged retainers. However, independent sample t-test indicated that this difference was statistically not significant.

Conclusion: The durability of the PEEK lingual retainer adhesive system has been confirmed using the well-known oral simulating artificial aging protocol of water storage and thermocycling.

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Publication Date
Mon Mar 08 2021
Journal Name
Baghdad Science Journal
On some types of almost periodic point in Bi-Topological dynamcs
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In this paper We introduce some new types of almost bi-periodic points in topological bitransfprmation groups and thier effects on some types of minimaliy in topological dynamics

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Publication Date
Fri Sep 01 2023
Journal Name
Iraqi Journal Of Physics
Influence of NiTi Spring Dimensions and Temperature on the Actuator Properties
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Nitinol (NiTi) is used in many medical applications, including hard tissue replacements, because of its suitable characteristics, including a close elastic modulus to that of bones. Due to the great importance of the mechanical properties of this material in tissue replacements, this work aims to study the hysteresis response in an attempt to explore the ability of the material to remember its previous mechanical state in addition to its ability to withstand stress and to obtain the optimal dimensions and specifications for the manufacturer of NiTi actuators. Stress-strain examination is done in a computational way using a mutable Lagoudas MATLAB code for various coil radii, environment temperatures, and coil lengths. The computational m

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Publication Date
Tue May 01 2012
Journal Name
Iraqi Journal Of Physics
Nano-Scale core effects on electronic structure properties of gallium arsenide
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Ab – initio density function theory (DFT) calculations coupled with Large Unit Cell (LUC) method were carried out to evaluate the electronic structure properties of III-V zinc blend (GaAs). The nano – scale that have dimension (1.56-2.04)nm. The Gaussian 03 computational packages has been employed through out this study to compute the electronic properties include lattice constant, energy gap, valence and conduction band width, total energy, cohesive energy and density of state etc. Results show that the total energy and energy gap are decreasing with increase the size of nano crystal . Results revealed that electronic properties converge to some limit as the size of LUC increase .

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Publication Date
Mon Jan 02 2017
Journal Name
Journal Of Educational And Psychological Researches
Effectiveness of fishbowl strategy on intermediate students’ achievement in geography subject
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The aim of this study is to examine the effectiveness of fishbowl strategy as one of the effective learning strategies for intermediate students’ achievement in geography subject. To do this, three classes of second intermediate were chosen from Noor Al-Mustafa School for academic years (2015-2016). (64) Student were selected as a sample that distributed into two equal groups: experimental and control group. The research used the achievement test as an instrument to come up with the finding of the study. The experiment began on Tuesday 13th of October 2015 and ended on Tuesday 5th January 2016. Through this time, the researcher taught them the first and second chapter in geography of Arab homeland using fishbowl s

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Publication Date
Sat Sep 30 2017
Journal Name
Al-khwarizmi Engineering Journal
Numerical Investigations on Heat Flow of Nanofluids in Ribs Tube Configurations
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Abstract

In this paper presents two dimensional turbulent flow of different nanofluids and ribs configuration in a circular tube have been numerically investigation using FLUENT 6.3.26. Two samples of CuO and, ZnO nanoparticles with 2% v/v concentration and 40 nm as nanoparticle diameter combined with trapezoidalribs with aspect ratio of p/d=5.72 in a constant tube surface heat flux were conducted for simulation. The results showed that heat flow as Nusselt number for all cases raises with Reynolds number and volume fraction of nanofluid, likewise the results also reveal that ZnO with volume fractions of 2% in trapezoidal ribs offered highest Nusselt number at Reynolds number of Re= 30000.

Key

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Publication Date
Mon Jun 05 2023
Journal Name
Journal Of Engineering
Nonlinear Analysis on Torsional Strengthening Of Rc Beams Using Cfrp Laminates
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This research is devoted to investigate the behavior and performance of reinforced concrete beams strengthened with externally bonded Carbon Fiber Reinforced Polymer (CFRP) laminates under the effect of torsion. In this study a theoretical analysis has been conducted using finite element code ANSYS. Six previously tested beams are used to investigate reinforced concrete beams behavior
under torsion, two of them are solid and the rest are box-section beams. Also, two beams are without CFRP reinforcement, which are used as control beams for the strengthened one, and the other four beams are strengthened with CFRP laminates with different number of layers and spacing. Numerical investigation is conducted on these beams, and comparisons b

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Publication Date
Sun Mar 30 2008
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Experimental Studies on the Benification of Fine Solids by Forth Flotation
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In this paper, the experiments were carried out in laboratory flotation cell treating solid fines. The effect of variables such as collector oil dosage, pine oil dosage and solid content of the feed slurry have been investigated on the flotation characteristics of low rank coal. Attempts have also been made to develop some empirical Eq. to predict the yield and ash content of concentrate with the operating variables, solids concentration, collector oil dosage, and pine oil dosage, to estimate the recovery at any operating conditions. The calculated results obtained from regression equation by correlating the variables with the yield and ash content of concentrate have been compared to study whether calculated values match closely with th

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Publication Date
Thu Jun 15 2023
Journal Name
International Journal Of Nanoscience
Fabrication and Enhancement of Organic Photodetectors Based on Iron Phthalocyanine Films
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Iron–phthalocyanine (FePc) organic photoconductive detector was fabricated using pulsed laser deposition (PLD) technique to work in ultraviolet (UV) and visible regions. The organic semiconductor material (iron phthalocyanine) was deposited on n-type silicon wafer (Si) substrates at different thicknesses (100, 200 and 300) nm. FePc organic photoconductive detector has been improved by two methods: the first is to manufacture the detector on PSi substrates, and the second is by coating the detector with polyamide–nylon polymer to enhance the photoconductivity of the FePc detector. The current–voltage (I–V) characteristics, responsivity, photocurrent gain, response time and the quantum efficiency of the fabricated photoconduc

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Publication Date
Sat Feb 01 2020
Journal Name
Alexandria Engineering Journal
Impact of development on Baghdad’s urban microclimate and human thermal comfort
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Publication Date
Tue Sep 26 2023
Journal Name
Brazilian Journal Of Biometrics
Bifurcation analysis of commensalism intraction and harvisting on food chain model
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In this paper, we study the incorporation of the commensalism interaction and harvesting on the Lotka–Volterra food chain model. The system provides one commensal prey, one harvested prey, and two predators. A set of preliminary results in local bifurcation analysis around each equilibrium point for the proposed model is discussed, such as saddle-node, transcritical and pitchfork. Some numerical analysis to confirm the accruing of local bifurcation is illustrated. To back up the conclusions of the mathematical study, a numerical simulation of the model is carried out with the help of the MATLAB program. It can be concluded that the system's coexistence can be achieved as long as the harvesting rate on the second prey population is

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