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.
This Kind of study has a special importance. Great numbers of Arab Muslims share a lot of their work, their Trans lations & new additions to scientific heritage. They facilitate the indirect way for Europeans to got Greek scientific knowledge. Ibn Sina classified & collected in his book (Law) Galen`s medical publications & he clarified, arranged & make them easy to understand.
يتناول البحث الحماية المدنية للمستهلك في المرحلة السابقة على التعاقد الالكتروني
يأخذ هذا النوع من الدراسات اهميته في مجال الكتابة التاريخية لما لها من اهمية في بناء التراث الفكري الحضاري للامة العربية الاسلامية.
La stylistique, héritière de la rhétorique, est ‘la science du style’. La stylistique
qui a commencé, dès son apparition, par être divisée en stylistique de l’expression et
stylistique génétique s’est vu connaître d’autres classements en stylistique idéaliste,
structuraliste, fonctionnaliste ; générativiste….etc.
Cette évolution continuelle reflète la richesse de cette discipline. La diversité des
courants et écoles dans ce domaine se traduit sur le champ par une variété de méthodes
d’analyse stylistique.
L’enjeu principal dans la plupart de ces méthodes d’analyse est la manière selon la
quelle la relation entre langue et parole, langu
... Show MoreThis research aims to know the reality of implementation of Knowledge Management in Saudi Universities Applied in Shaqra University and to study the difficults whish encountered in applying the Knowledge Management approach.
The study investigated the university staff in Shaqra, Thadig, and Huraymila branches, using a questionnaire designed by the researcher to collect the data, sample of (260) members was used, applying the descriptive analytical approach to test the hypothesis by using (SPSS) program.
The study revealed that the first four zero hypothesis are rejected because there is medium approval of the university members on the fo
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The theme of the Abbasid Caliph and their children great interest in the knowledge and effective not only in the history of civilization but in the history of the humanity and the sublime values. Their interest and care for the scholar ulamaa and rendering help and encouragement by their caliphs were keen for science and knowledge because whatever the scholars have a status they cannot give help without and knowledge and the practice of their role in the interest and the care.
تعد التنمية المستدامة حق للكل البشرية وانها تهدف لتطوير المجتمعات البشرية من كافة النواحي وبشكل دائم وهي تهدف في القضاء على الفقر والجوع وهذه الظاهر ظاهرة منتشرة في العراق اذ ان المواطنين فيه يعشون في حالات تفرقة ودائما هم في حالات حروب اويعيشون في حصار اقتصادي او في اوقات كثيرة يعشون باوقات ازمات مما يجعلهم في فقر دوري ارض لتطبيق هدف التنمية المستدامة الذي ينص على القضاء على ،
The present study was carried out to investigate the effect of oral administration of hot aqueous extract of beetle cocoon Larinus maculatus Faldermann, in a two doses 50 and100mg/Kg/Bw for 25 and 45days respect- tively on some organs such as liver, lung, kidney, intestine, heart, spleen, and brain in male mice Mus musculus. The results indicated that there were toxicopathological changes in many tissues of experimental animals. Histo -pathological changes was dose and period dependent . It was found that the aqueous extract of beetle cocoon has undesirable effect at the administered doses, since the raw extract of this cocoon is currently being used in Folk medicine as treatment for cough, bronchitis in Iraq. This study revealed that the l
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