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Influence of Fractional CO2 Laser Irradiation on Temperature Elevation and Bonding Strength of Resin Cement to the Zirconia Ceramic
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Abstract: Objectives: To investigate the effect of temperature elevation on the bonding strength of resin cement to the zirconia ceramic using fractional CO2 laser. Background: Fractional CO2 laser is an effective surface treatment of zirconia ceramic, as it increases the bonding strength of zirconia to resin cement. Methods: Thirty sintered zirconia discs (10 mm diameter, 2 mm thickness) were prepared and divided to three groups (N=10) and five diffident pulse durations were used in each group (0.1, 0.5, 1, 5 and 10 ms). Group A was treated with 10 W power setting, group B with 20 W and group C with 30 W. During laser irradiation, temperature elevation measurement was recorded for each specimen. Luting cement was bonded to the treated zirconia surfaces and cured for 30 seconds. Shear bond strength was evaluated by a testing machine (universal) with bond failure mode determination. Results: The lowest temperature elevation measurement of the irradiated specimen which gave maximum shear bond strength was about 1.6±0.3 Ċ higher than ambient room temperature (27±0.2 ºC). Apparent micromechanical irregularities were seen in the treated samples and cracks formation with increased pulse duration and power setting were also observed. Conclusions: The temperature elevation is a vital factor in the surface roughness of zirconia ceramic with fractional CO2 laser irradiation and the lowest temperature elevation at best shear bond strength of zirconia ceramic to the resin cement is satisfied with the shorter pulse duration of 0.1 millisecond.

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Publication Date
Tue Oct 23 2018
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of Dividend Policy on Earnings Quality in The Companies listed in Iraq Stock Exchange
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The dividends is one of difficult and important decisions taken by the administration in the economic units, because this decision has a direct impact on the investor and economic unit, so the main objective of any investor is achieve earnings, as well as information borne by dividends about the earnings quality of the economic unit and the level and efficiency of management to achieving earnings.

The research aims at explaining the effect of the dividends policy on the earnings quality in the companies listed in the Iraq Stock Exchange. The Miller model was used to measu

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Publication Date
Wed Aug 05 2020
Journal Name
Neuroquantology
The Influence of Some Important Parameters on the Performance Efficiency of the Compound Parabolic Solar Concentrator
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Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
Study the Effect of Face Sheets Material on Strength of Sandwich Plates with Circular Hole
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This study aims to investigate the effect of changing skins material on the strength of sandwich plates with circular hole when subjected to mechanical loads. Theoretical, numerical and experimental analyses are done for sandwich plates with hole and with two face sheet materials. Theoretical analysis is performed by using sandwich plate theory which depends on the first order shear deformation theory for plates subjected to tension and bending separately. Finite element method was used to analyse numerically all cases by ANSYS program.

The sandwich plates were investigated experimentally under bending and buckling load separately. The relationship between stresses and the ratio of hole diameter to plate width (d/b) are built, by

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Publication Date
Mon Aug 01 2011
Journal Name
Journal Of Engineering
EFFECT OF STEEL FIBERS ADDITION ON THE BEHAVIOR OF HIGH STRENGTH CONCRETE CIRCULAR SHORT COLUMNS
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loaded reinforced concrete circular short columns. An experimental investigation into the behavior
of 24 short reinforced concrete columns with and without steel fibers was carried out. The columns
had a circular section (200 mm diameter and 900 mm long). Test variables include concrete
strength, spacing of spiral reinforcement, and inclusion of steel fibers. The axial stress and axial
strains were obtained and used to evaluate the effects of the presence of steel fibers. It was found
that the addition of steel fibers slightly improves the load carrying capacity of the tested columns
whereas it significantly enhances the ductility of these specimens. Test results also indicated that for
the same confinement parameter

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Publication Date
Thu Jan 29 2026
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of anti-oxidant agents as neutralizers of bleaching agents on dentin bond strength
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Background: Reduction in bond strength when bonding was done immediately after intracoronal bleaching procedure has been recognized. The purpose of this study is to assess the effect of antioxidants (10% sodium ascorbate (SA), 0.1M thiourea and7% sodium bicarbonate (SB)) on reversing bonding strength of composite resin to bleached dentin. Materials and method: Sixty upper 1st premolar teeth, were selected, the crowns of the teeth were embedded in acrylic resin blocks exposing a flat dentin from the buccal surface, then divided into 6 groups (10 samples each). Bleaching for the experimental groups was performed using 35% hydrogen peroxide bleaching gel (pola–office).Group A (Negative

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Publication Date
Mon Nov 05 2018
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
EFFECT OF PLANT DENSITIES ON THE GROWTH AND YIELD OF SUNFLOWER Helianthus annuus L.: EFFECT OF PLANT DENSITIES ON THE GROWTH AND YIELD OF SUNFLOWER Helianthus annuus L.
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A field experiment was conducted at the experimental field of botanical garden, faculty of science, university of Baghdad, in order to study the effect of plant density on growth and yield of two local cultivars of sunflower (Sin Althieb and Shumose). The densities used were 4.4 and 8.8 plant/m2. The results showed difference between cultivars in their agronomic traits and their yields. There was a significant increase in plant height and leaf area index by increasing the plant density, while head diameter, number of seeds and leaf area decreased. But the most significant effect was the increasing in yield and biological yield by increasing the plant density. There was an increase by 72% and 58% in the yield and 79% an

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Publication Date
Sun Dec 15 2019
Journal Name
Journal Of Baghdad College Of Dentistry
The Effects of Nano Alumina On Mechanical Properties of Room Temperature Vulcanized Maxillofacial Silicone (Pilot Study)
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Background: Facial disfigurement can be the result of a congenital anomaly, trauma or tumor surgery, in many cases the prosthetic rehabilitation is indicated. Maxillofacial prosthetic materials should have desirable and ideal physical, aesthetic, and biological properties and those properties should be kept for long period of time in order to reach patient acceptance. Silicone elastomer are the most commonly used material for facial restoration because of its favorable properties mechanically and physically as the biocompatibility and good elasticity. Aim of this study: This study aimed to evaluate the effect of addition of Aluminum oxide (Al2O3) Nano fillers in different concentrations on tear strength and hardness of VST 50F room tempe

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Publication Date
Fri Jul 21 2023
Journal Name
Journal Of Engineering
Effect of Fire Flame (High Temperature) on the Behaviour of Axially loaded Reinforced SCC Short Columns
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Experimental research was carried out to investigate the effect of fire flame (high temperature) on specimens of short columns manufactured using SCC (Self compacted concrete). To simulate the real practical fire disasters, the specimens were exposed to high
temperature flame, using furnace manufactured for this purpose. The column specimens were cooled in two ways. In the first the specimens were left in the air and suddenly cooled using water, after that the specimens were loaded to study the effect of degree of
temperature, steel reinforcement ratio and cooling rate, on the load carrying capacity of the reinforced concrete column specimens. The results will be compared with behaviour of columns without burning (control specime

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Publication Date
Mon Dec 31 2018
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
EFFECT OF PLASTIC WASTES AS LOW COST MATERIAL ON SOME PROPERTIES OF UNSATURATED POLYESTER.: EFFECT OF PLASTIC WASTES AS LOW COST MATERIAL ON SOME PROPERTIES OF UNSATURATED POLYESTER.
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In this study, plastic wastes named (PET and PVC) were used to prepare polymer matrix composite (PMC) which can be used in different applications. Composite materials were prepared by mixing unsaturated polyester resin (UP) with plastic wastes, two types of plastic waste were used in this work included polyethylene-terephthalate (PET) and Polyvinyl chloride (PVC) with various weight fractions (0, 5,10,15, 20 and 25%) added as a filler in flakes form. In this work, some of the tests that were carried out included (tensile, bending, and compressive strength) as mechanical tests, in addition to (thermal conductivity and water absorption) as physical tests. The values of tensile, compressive strength and Young's modulus of UP increased after

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Publication Date
Tue Dec 13 2011
Journal Name
Iraqi Journal Of Laser
The Effect of 532nm Nd: YAG Pulsed Laser on the Activity of Superoxide dismutase and Alcoholdehydrogenase of Saccharomyces Cerevisiae
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In this study, the effect of Nd: YAG laser on the activity of superoxide dismutase (SOD) and alcoholdehydrogenase (ADH) was investigated. The Saccharomyces cells were irradiated using 532nm Q-Switched Nd: YAG laser with (1Hz) frequency. Different fluences 11.3, 22.6 and 33.9mJ/cm2 and different number of pulses 15, 30 and 60 pulse were used. The irradiated cells were incubated in a liquid nutritive medium for 24 hours. After incubation, the cells were harvested and disrupted to extract the intracellular enzymes and their activities were assessed. In comparison with the control, the irradiated cells showed a significant increase in the activity and the specific activity of SOD at energy densities of 11.3 and 22.6mJ/cm2 at 30 and 60 pulses

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