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.
Banks face many of the various risks: which are of dangerous phenomena that cause the state achieved a waste of money and a threat to future development plans to be applied to reach the goals set by: prompting banks and departments to find appropriate solutions and fast: and it was within these solutions rely on Banking risk management and effective role in defining and identifying: measuring and monitoring risk and trying to control and take risks is expected to occur in order to encircle and make it in within acceptable limits: and try to avoid them in the future to reduce the losses that are likely to be exposed to the bank: and it began to emerge and dominate a lot of legislation that seeks to structure the year risk management and t
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This paper presents the effect of Cr doping on the optical and structural properties of TiO2 films synthesized by sol-gel and deposited by the dip- coating technique. The characteristics of pure and Cr-doped TiO2 were studied by absorption and X-ray diffraction measurement. The spectrum of UV absorption of TiO2 chromium concentrations indicates a red shift; therefore, the energy gap decreases with increased doping. The minimum value of energy gap (2.5 eV) is found at concentration of 4 %. XRD measurements show that the anatase phase is shown for all thin films. Surface morphology measurement by atomic force microscope (AFM) showed that the roughness of thin films decrease with doping and has a minimum value with 4 wt % doping ratio.
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Little is known about hesitancy to receive the COVID‐19 vaccines. The objectives of this study were (1) to assess the perceptions of healthcare workers (HCWs) and the general population regarding the COVID‐19 vaccines, (2) to evaluate factors influencing the acceptance of vaccination using the health belief model (HBM), and (3) to qualitatively explore the suggested intervention strategies to promote the vaccination.
This was a cross‐sectional study based on electronic survey data that was collected in Iraq during December first‐19th, 2020. The electronic surve
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The aims of research is to identify the role of strategic human resource management Practices in organizational performance improvement in the Baghdad soft drinks company, as well as the implications of the results for both managers and practitioners.
In order to achieve the objectives of the research, the researcher designed questionnaire included (40) items to collect the initial data from the research sample consisting of (53) Single. In light of that has been collecting and analyzing data and test hypotheses using the statistical package for Social Sciences (SPSS21), and use a number of statistical methods to achieve the goal of the research, including the means, standard deviations and simple correla
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يهدف البحث إلى تقييم الكفاءة الوظيفية لمؤسسات التعليم الأهلي في أداء وظيفتها بمستوى عالٍ لتشبع حاجة سكان المدينة الذين فضّلوا التعليم الأهلي على التعليم داخل المؤسسات الحكومية مما أدى إلى انتشارها، وصولا إلى أهم الآثار المترتبة على ذلك الانتشار إذ نافست فيه مؤسسات التعليم الحكومي، بل وتنافست المؤسسات الأهلية فيما بينها لتقديم أفضل خدمة تعليمية للصراع من أجل البقاء، وتهدف أيضا إلى إظهار الوجه السلبي ا
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إن اختلاف الفقهاء مصدر عظيم لثروة فقهية كبيرة، ومن مظاهر الخلاف الفقهي مؤاخذات علمية يوردها بعض العلماء على علماء آخرين بدعوى مخالفتهم الأدلة الشرعية، أو القواعد المقررة لاستنباط الأحكام الشرعية، ومن تلك المؤاخذات ما أورده الإمام المحدث أبو بكر ابن أبي شيبة رحمه الله تعالى على أبي حنيفة النعمان رحمه الله حيث إنه ساق في مصنفه الكثير من الأحاديث والآثار التي عد الإمام أبا حنيفة رحمه الله مخالفا لما تقتضيه من
... Show MoreIt may say that of difference towards a state that had witnessed the birth of modern party system in England ،and it appear a new case of organization and use ways effecting in general opinion through the election parties that had different in their ideology as Alweel party which dealt with religion related among its members with Buretan with its members participation understandings of free expression of their opinions trying to fight the control of Christ men in a time that Tory party was Enklikanian more than as it was loyalty one .
يعد الدين من أكثر المتغيرات تأثيرا في سلوك البشر بصورة عامة ، وفي شخصياتهم وصحتهم النفسية بصورة خاصة .
ولأحداث الحياة والأزمات والشدائد تأثيرها الكبير في هذا المتغير وفي مدى تمسك الناس بقيمهم الدينية .
وفي العراق ، لا تخفى علينا المآسي والأزمات والشدائد التي مر ويمر بها البلد مما قد يزعزع ثقة الناس بمعتقداتهم وقيمهم ، ومن جانب آخر فان دخول المحت
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