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.
ملخص البحث: تعتبر مشكلة تعاطي المخدرات من المشكلات التي تؤثر في بناء المجتمع وأفراده لما يترتب عليها من آثار اجتماعية واقتصادية ونفسية سيئة تنسحب على الفرد و على المجتمع، كما أنها ظاهرة اجتماعية مرضية تدفع إليها عوامل عديدة؛ بعضها يتعلق بالفرد والبعض الآخر بالأسرة والثالث بالبناء الاجتماعي ككل. وتعد ظاهرة انتشار المخدرات من الظواهر الأكثر تعقيدا وبارزة هذه الظاهر ة وإحدى مشكلات العصر، الشاملة في المجتمع، و
... Show MoreThe poetic necessity in evidence to explain Ibn Aqeel were not alike, came a statement from him as a necessity in some verses and the other came as abnormal, differentiating it from the language, but he never mentioned in some verses in which the need as a necessity,
يمكن القول ، أن أزمة الاستبعاد والخلاف بشان ولاية العهد شهدت ولادة النظام الحزبي الحديث في إنكلترا، واظهرت حالة جديدة للتنظيم والدعاية الحزبية وادخال طرق جديدة للتأثير في الرأي العام في اثناء الانتخابات، واختلفت تلك الاحزاب في ايديولوجياتها فحزب الويك كانت له ارتباطات دينية بين اعضائه مع البيورتان أذ تشاركوا في مفاهيم حرية التعبير عن الرأي ومقاومة هيمنة رجال الكنيسة المتنفذين، في حين كان حزب التور
... Show MoreThe biometric-based keys generation represents the utilization of the extracted features from the human anatomical (physiological) traits like a fingerprint, retina, etc. or behavioral traits like a signature. The retina biometric has inherent robustness, therefore, it is capable of generating random keys with a higher security level compared to the other biometric traits. In this paper, an effective system to generate secure, robust and unique random keys based on retina features has been proposed for cryptographic applications. The retina features are extracted by using the algorithm of glowworm swarm optimization (GSO) that provides promising results through the experiments using the standard retina databases. Additionally, in order t
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تعد ظاهرة الصراعات ظاهرة قديمة كقدم الوجود البشري وهذا يطبق على المستوى الدولي مما يجعل الدول الصغرى هي ساحة تصفيات كما هو الحال في سوريا مما يجعل الامن الانساني فيها معدوم
بعض الملاحظات على القانون رقم 35 لسنة 2007 قانون العمل الصحفي في كوردستان
ابعاد الجودة في السيطرة على العدوى المكتسبة في المستشفيات الحكومية العراقية: دراسة تقويمية
This research submitted to be a clear form for a city has famous civilization extended many centuries , made its obvious stamps & prominent for eyesight through what left us of edifices stated witnesses of Islamic cities , that are distinguished from others by its model , engineering of buildings that are taken special characteristics display thought creativity features & Islamic Arabian art , and this research clarifies from thought & design of Al-Hajjaj in building Wasit City that appeared as a result from the political conditions that Iraq faced them in general , and Al-Hajjaj in particular , the increasing of revolutions from different governorates
The research(the internal and external factors affecting the political system in
PAKISTAN) involves a series of effects interact both internally and external to affect the
stsbility of the political system.
Intrernally there are a lot of powers affecting the political map of PAKISTAN such as
military institution, political parties, judgement, religious schools……etc.of internal
factors, which represent one of the most important pressure points on the system.
Externally one of the most important external factors which affect internal stability is
Pakistani allision to USA in antiterrorism war. The Pakistani military institution was
involved in the war against Pakistani tribes leading to unstable security in Paki
اهتم في الربع الأول بالمفاهيم النظرية للمناهج التي تقع في النقاط الخمس ، النقطة الأولى تتعلق بمفهوم الخطاب والخطاب المادي ، وقلنا أن الرسالة كانت مبنية على الجسد من البداية ، حتى قبل ذلك هناك ستكون فلسفة أو معرفة المنظمة. أما النقطة الثانية فتتعلق بالمفهوم الفينومينولوجي للخطاب ، ونحن في هذه المرحلة أهم الركائز التي قام عليها (إدموند هوسرل) في بناء مفهوم وصفي ضعيف. في النقطة الثالثة نكشف عن الظواهر المتعلقة ب
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