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.
Talking about the importance of the imagination in sculptural works has a role in shaping the collective memory and moving it, whether it is an artistic, social, religious or historical imagination. Because it documents the cultural heritage of any country through the structural structure of the sculptural form, and its connotations and symbols, which are considered an effective aesthetic image in the crystallization of various intellectual concepts and contents.
Therefore, the study aimed to know the employment of the popular imagination in the artistic works of the sculptor (Muhammad Ghani Hikmat), as well as to reveal the artistic and aesthetic features of the folklore and its reflection on its artistic style. And the references
The bifurcation of the constitutional rights of one of the techniques used by the constitutional court to expand the scope of the constitutional right to explicit, and access to the fact that guarantees constitutional rights, and establishes the constitutional elimination of this technique on a particular bond is the constitutional terms of reference, and in the light of his discretion in the exercise of the constitutional powers of , and tends at times To the adoption of a broad branching approach, which confers on the constitutional text containing constitutional rights a wider scope than the scope of an explicit right.
The semantic analysis is characterized by its ability to describe the communicative pattern and its high efficiency in questioning its semantic manifestations and its deliberative purposes, which helped to understand the symbolic, contextual and cultural manifestations of the structure of the pattern, whether verbal or nonverbal. In order to highlight the role of the semiautomatic approach and its application to a sample of slogans collected from "media, social networking sites, in-kind views, media institutions, etc." to study the components and analyze the contents and highlight the signs. His boat logo is not just uttered as a linguistic transmission of a message, but as a political Tghieria actually . For example, the slogan "People Wan
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The American vision of the Non-governmental Organizations in Iraq the topic area of that’s paper dealing with Civil Society as concept and practice, its already consider as Western concept and associated with liberalism and political development, they are many definitions of its but most significantly is all organizations, agencies, trade unions and non-governmental institutions, that’s agencies were established after 2003 and received funds from United States and UN development agencies. The non- governments organizations played a significant role as support and develop many cultural, healthy, educational, and social projects, also that’s organizations try to reduction the effects of terrorists actions especially after ISI
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The present research aims at recognizing the difficulties and problems which hamper teachers and educators alike when using the internet for educational purposes.It discusses the benefits of the internet as a source of information or publication and as a communicative tool.Arandom sample of (30) teachers working at schools in Baghdad / Second Risafa,was selected.Three of the sample members use the internet for student project plans via internet centers, whereas 16 of them use it for chatting, emailing and research purposes.The rest of the sample have limited knowledge of the internet. The researcher used the interviewing method to gather data from
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This research is an initial attempt to explore the reality of education and its concept in Islam, and to describe the presence of educational practices in the Arab-Islamic heritage. The importance of this research lies in addressing a set of important issues related to the contemporary Islamic educational system. The research revealed the extent of the need for authentic educational values that draw their reference from the origins of Islam, and it emphasized the analysis of the reality of education in the Islamic world and the identification of its problems and the finding of solutions through a quick and comprehensive look at the diverse contributions of Muslimthinkers to Islamic educational thought, and their active ro
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during the decomposition CaC03 are identified. The role of the C02 equilibrium pressure is examined in relation to the kinetic compensation effect. This investigation also shows why non - iso thermal experiments have some time necessarily to yield value of activation energy different from the value obtained from isothermal experiments.