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.
A total of 23 samples are collected from Injana and Mukdadiya Formations representing: sandstone (14 samples from Injana Formation and 9 samples from Mukdadiya Formation). 19 sandstone samples are thin sectioned for petrographic study (10 thin sections from Injana and 9 thin sections from Mukdadiya) and 23 sandstone samples are selected for heavy minerals study (14 samples from Injana and 9 samples from Mukdadiya). The petrographic investigations revealed that the sandstone of Injana and Mukdadiya Formations are composed primarily of rock fragments (sedimentary, igneous and metamorphic), quartz (monocrystalline and polycrystalline) and feldspars (orthoclase, microcline and plagioclase). The matrix is subordinate and the cement is mostly
... Show MoreElectro-kinetic remediation technology is one of the developing technologies that offer great promise for the cleanup of soils contaminated with heavy metals. A numerical model was formulated to simulate copper (Cu) transport under an electric field using one-dimensional diffusion-advection equations describing the contaminant transport driven by chemical and electrical gradients in soil during the electro-kinetic remediation as a function of time and space. This model included complex physicochemical factors affecting the transport phenomena, such as soil pH value, aqueous phase reaction, adsorption, and precipitation. One-dimensional finitedifference computer program successfully predicted meaningful values for soil pH profiles and Cu
... Show MoreHigh performance liquid chromatography was applied for the separation and identification of four antharquinone derivatives, aloe emodin, emodin, chrysophanol and physcion. The separation was carried out using Eurospher 100, C18 column (4.6 mm i.d. x 250 mm, 5 µm) under the following conditions: acetonitile (solvent A) and water: acetic acid (99.9: 0.1 v/v, pH 3.5)( solvent B) as a mobile phase with isocratic elution with 30% solvent B at flow rate 0.8 ml/min. The detection wavelength was set at 254 nm. The four antharquinone derivatives were isolated from the Iraqi rhubarb, Rheum ribes root by preparative TLC, their structures were identified by 1H NMR and used as standards for HPLC analysis. The percentages of alo
... Show MoreThis study aims to demonstrate the morphotectonic evidence (drainage pattern, formations of sedimentary rocks, structural ridge deformations and spectral reflectance differences…etc.) for tectonic uplift with the syncline zone between two major anticlines, Kirkuk anticline in the northeast and Qara Chauq anticline in the southwest. The study area is located in the low folded zone at the geographical coordinates of 35º 45´ to 35º 55´ North and 43º 30´ to 44º 00´ East. In this study, the tectonic uplift was named as Dushwan uplift, because the uplift of the rocks was adjacent to Dushwan village.
The regional stress, originating from the collision of the Arabian plate with the E
... Show MoreThe ground state density distributions and electron scattering Coulomb form factors of Helium (4,6,8He) and Phosphorate (27,31P) isotopes are investigated in the framework of nuclear shell model. For stable (4He) and (31P) nuclei, the core and valence parts are studied through Harmonic-oscillator (HO) and Hulthen potentials. Correspondingly, for exotic (6,8He) and (27P) nuclei, the HO potential is applied to the core parts only, while the Hulthen potential is applied to valence parts. The parameters for HO and Hulthen are chosen to reproduce the available experimental size radii for all nuclei under study. Finally, the CO component of electron scattering charge fo
... Show MoreThe accuracy of the skillful performance of the front and back dimensions of badminton in volleyball, occurs through the investment of complex exercises (physical skills) in a single performance and its characteristics that give the correct movement behavior and speed to the accuracy of the performance of the strokes as well as the identification of changes in some physiological indicators of By using these compound exercises. The research problem lies: I found a weakness in the accuracy of the performance of the front and back dimensions strike and diagnosed this through the tests that it conducted on the players to identify and know the problem, and attributed this weakness to a weakness in the necessary physical and skill abilities and t
... Show MoreThe study aimed to identify self –affirmation degree, tendency degree toward perfection, awareness degree of creativity among fine arts institutions students, and the significant correlation between self -affirmation and its tendency toward perfection, and the awareness of creativity among fine arts institutions students. To achieve these objectives, the author had constructed two scales: one to measure self –affirmation among the sample based on “Lang& Jakobowski theory” (Lang& Jakobowski, 1973) that consisted of (54) item divided into two parts: qualitative and situational. The other scale is to measure the tendency toward perfection depend on (flett & Hewitt, 1991) that composed of (46) item divided into two sectio
... Show MoreIn the present study the radon concentration was measured in indoor places by the RAD7 (radon detector) was in some locations at Al-Tuwaitha nuclear site and some surrounding areas for the duration from 13/10/2016 to 2/1/2017 and the measurement of the indoor radon concentration ranged from (4.96±4.4 to 102±25) Bq/m3. The high value of radon has been found at decommissioning directorate /emergency room, which is lower than the action value recommended by the Environmental Protection Agency (EPA) which is (148 Bq/m3) while the lowest value has been founded in central laboratories directorate \ models room. These values were used to calculate the annual effective dose and the health risks for cells bronchial which caused by the inhalatio
... Show MoreAbstract:
Investment in human capital of renewable energy can be relied upon to get to achieve the goals of development is important for Iraq through the intellectual community cards creative able to innovate and develop what is so is study the effect of human investment on economic growth through the adoption of the index of national income as a function of variables independent ( human capital, physical capital) and this is built on the premise that the relationship direct correlation between economic growth and human investment, and it can measure the return on human investment, which is an incentive to increase human capital through education and the development of the economy in general have shown th
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