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Fracture strength of laminate veneers using different restorative materials and techniques (A comparative in vitro stuy)
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Background: Esthetic correction represents one of the clinical conditions that required the use of laminate veneers in premolars region. Aim of the study: The purpose of this study was to evaluate the fracture strength of the laminate veneers in maxillary first premolars, fabricated from either composite (direct and indirect techniques) or ceramic CAD/CAM blocks. Materials and Methods: Fifty sound human maxillary premolar teeth were used in this in vitro study. Teeth were divided randomly into one control group and four experimental groups of ten teeth each; Group A: Restored with direct composite veneer (Filtek Z250 XT), Group B: Restored with indirect composite veneers (Filtek Z250 XT), Group C: Restored with lithium disilicate ceramic CAD/CAM blocks (IPS e. max CAD) and Group D: Restored with resin nano ceramic CAD/CAM blocks (Lava Ultimate Restorative). Standard preparations were done using Ceramic Veneer Set (Komet). Indirect laminate veneers were cemented with the Relyx Veneer Cement (3M ESPE) and all specimens were stored in distilled water at 37°C for 2 weeks. The load was applied on the occlusal part of the veneer at 45˚ to long axis of the tooth using universal testing machine. Results were analyzed with one-way ANOVA and LSD tests. Specimens were examined by stereomicroscope at a magnification of 20x to evaluate the mode of failure. Results: Control group showed higher mean of fracture strength with highly significant difference in comparison to the experimental groups (P<0.01). (Group A) showed higher mean of fracture strength with statistically significant difference in comparison to (Group B and Group D). On the other hand the difference between (Group A and Group C) was statistically highly significant. Statistically non-significant difference was found among the three indirectly restored groups. Conclusions: All veneers used in this study can be considered as acceptable treatment in the premolars region for patients with normal biting force. Direct composite veneer is the most favorable technique in term of fracture strength, while IPS e. max CAD laminate veneers were least likely to fracture and most likely to completely debond.

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Publication Date
Sun Jan 14 2018
Journal Name
Journal Of Engineering
Optimum Design of Power System Stabilizer based on Improved Ant Colony Optimization Algorithm
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This paper presents an improved technique on Ant Colony Optimization (ACO) algorithm. The procedure is applied on Single Machine with Infinite Bus (SMIB) system with power system stabilizer (PSS) at three different loading regimes. The simulations are made by using MATLAB software. The results show that by using Improved Ant Colony Optimization (IACO) the system will give better performance with less number of iterations as it compared with a previous modification on ACO. In addition, the probability of selecting the arc depends on the best ant performance and the evaporation rate.

 

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Publication Date
Wed Jan 28 2015
Journal Name
Al-khwarizmi Engineering Journal
Thermal Field Analysis of Oblique Machining Process with Infrared Image for AA6063-T6
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Abstract

 Metal cutting processes still represent the largest class of manufacturing operations. Turning is the most commonly employed material removal process. This research focuses on analysis of the thermal field of the oblique machining process. Finite element method (FEM) software DEFORM 3D V10.2 was used together with experimental work carried out using infrared image equipment, which include both hardware and software simulations. The thermal experiments are conducted with AA6063-T6, using different tool obliquity, cutting speeds and feed rates. The results show that the temperature relatively decreased when tool obliquity increases at different cutting speeds and feed rates, also it

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Publication Date
Sun Nov 01 2015
Journal Name
Journal Of Engineering
Enhancement Solution to Improve Remediation of Soil Contaminated with Lead by Electrical Field
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A laboratory investigation of six different tests were conducted on silty clay soil spiked with lead in concentrations of 1500 mg/kg. A constant DC voltage gradient of 1 V/cm was applied for all these tests with duration of 7 days remediation process for each test. Different purging solutions and addition configurations, i.e. injection wells, were investigated experimentally to enhance the removal of lead from Iraqi soil during electro-kinetic remediation process. The experimental results showed that the overall removal efficiency of lead for tests conducted with distilled water, 0.1 M acetic acid, 0.2 M EDTA and 1 M  ammonium citrate as the purging solutions were equal to 18 %, 37 %, 42 %, and 29 %, respectively. H

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Publication Date
Sun Nov 01 2015
Journal Name
Journal Of Engineering
Treatment of Wastewater Contaminated with Pesticide (Alachlor) by Solar Enhanced Advanced Oxidation Processes
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The degradation performance of aqueous solution of pesticide Alachlor has been studied at solar pilot scale plant in two photocatalytic systems: homogeneous photocatalysis by photo-Fenton and heterogeneous photocatalysis with titanium dioxide. The pilot scale system included of compound parabolic collectors specially designed for solar photocatalytic applications, and installed at University of Baghdad, Department of Environmental Engineering back yard. The influence of different concentrations, H2O2 (200-2400 mg/l), Fe+2(5- 30 mg/l) and TiO2 (100-500 mg/l) and their relationship with the degradation efficiency were studied.

      The COD removal efficienc

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Publication Date
Wed Jun 01 2022
Journal Name
Iraqi Journal Of Physics
Evaluation of Mechanical Properties for Epoxy reinforced with palm oil /Zinc oxide composites
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In this research, the effect of reinforcing epoxy resin composites with a filler derived from chopped agriculture waste from oil palm (OP). Epoxy/OP composites were formed by dispersing (1, 3, 5, and 10 wt%) OP filler using a high-speed mechanical stirrer utilizing a hand lay-up method. The effect of adding zinc oxide (ZnO) nanoparticles, with an average size of 10-30 nm, with different wt% (1,2,3, and 5wt%) to the epoxy/oil palm composite,  on the behavior of an epoxy/oil palm composite was studied with different ratios (1,2,3, and 5wt%) and an average size of  10-30 nm.  Fourier Transform Infrared (FTIR) spectrometry and mechanical properties (tensile, impact, hardness, and wear rate) were used to examine the composites. The FTIR

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Publication Date
Thu Dec 01 2022
Journal Name
Environmental Nanotechnology, Monitoring & Management
Boosted visible-light-driven photocatalytic degradation of lomefloxacin over α-Ag2WO4/NiSx nanocomposites
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Publication Date
Sun Dec 01 2002
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
EXTERNAL MORPHOLOGICAL STUDY OF THE LEAFHOPPER EMPOASCA DECEDENS PAOLI (HOMOPTERA: CICADELLIDAE) FROM IRAQ
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This work presents external morphological study of the leafhopper Empoasca decedens
Paoli, 1932 particularly male genitalia, which were dissected and illustrated.
The genus Empoasca Walsh (Typhlocybinae: Empoascini) contains small, slender, fragile
and generally green leafhoppers. The overall length ranges from 3-3.5 mm. Members of this
genus are charachterized by their uniformly green color, inner and outer apical cells of
forewing not attaining wing apex, second and third apical cells are sessile or triangular or
even short stalked, submarginal vein of hindwing extends around wing apex and turned
beneath costal margin, apical thirds of tibiae and tarsal segments including claws are
prominently green while other

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Publication Date
Sun Oct 21 2018
Journal Name
Al–bahith Al–a'alami
The credibility of the official government spokesman to the Iraqi public / Survey Study
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The official spokesperson considered responsible for the transmission of information and communication messages that convey the government’s view on the various political and economic issues that affect the public opinion towards the performance achieved by the various governmental institutions and for the purpose of communicating with the media in a positive and effective manner, a number of institutions in the world in general and in Iraq in particular have nominated a spokesman to coordinate the efforts and the dissemination of news and the preparation of press conferences to contribute to the achievement of a positive and effective level between the government and the media, so this study has tackled to deal with the credibility of

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Publication Date
Fri Sep 01 2006
Journal Name
Journal Of Thermoplastic Composite Materials
The Thermoelectrical Behavior of PEO Films Doped with MnCl<sub>2</sub> Salt
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The poly(ethylene oxide) polymer (PEO) is doped with fine powder of MnCl2 salt and thin films of thickness (50–150 mm) with salt content (0, 5, 10, 15, and 20 wt%) are obtained. The AC electrical conductivity and dielectric constants are studied as a function of temperature through an impedance technique. It is found that AC conductivity increases and the calculated activation energy decreases with increasing temperature due to enhancement of the ionic conduction in the film bulk. The dielectric constants of the doped membranes increase with temperature. It is found that the peak value of the tanloss is shifted to a higher frequency at higher temperatures. The dielectric behavior is explained on the basis of

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Publication Date
Mon Dec 20 2021
Journal Name
Baghdad Science Journal
Numerical Analysis of Least-Squares Group Finite Element Method for Coupled Burgers' Problem
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In this paper, a least squares group finite element method for solving coupled Burgers' problem in   2-D is presented. A fully discrete formulation of least squares finite element method is analyzed, the backward-Euler scheme for the time variable is considered, the discretization with respect to space variable is applied as biquadratic quadrangular elements with nine nodes for each element. The continuity, ellipticity, stability condition and error estimate of least squares group finite element method are proved.  The theoretical results  show that the error estimate of this method is . The numerical results are compared with the exact solution and other available literature when the convection-dominated case to illustrate the effic

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