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.
The Arab economy suffers from many structural imbalances problems which are getting complicated by the appearance of the world economic variables.
This change held risky challenges for the Arab economies in the light of unsuitable regional and international conditions. Since that it has been very essential for the Arab experts, especially those related to economy and politics, to face those new challenges or, at least, adapt with them believing that they can have both positive and negative impacts on the Arab economy.
This study has acquired its importance in the light of the critical levels the Arab economy reached out of the world economic variables, resulting in long-term
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The design and implementation of an active router architecture that enables flexible network programmability based on so-called "user components" will be presents. This active router is designed to provide maximum flexibility for the development of future network functionality and services. The designed router concentrated mainly on the use of Windows Operating System, enhancing the Active Network Encapsulating Protocol (ANEP). Enhancing ANEP gains a service composition scheme which enables flexible programmability through integration of user components into the router's data path. Also an extended program that creates and then injects data packets into the network stack of the testing machine will be proposed, we will call this program
... Show Moreاضاءات على الانتخابات الشريعية في العراق عام 2010
Abstract
The developments of technology and information that is sweeping the world based on the factors of pressure on the accounting profession in general, and the authors of the accounting information. That becouse the makers of administrative decisions have become in need of new information fit and the environmental situation of the new competition and try to enter new markets,
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תקציר
העיון הזה מדבר על דבר ההשגה על הטקסטים המקראיים בידי כמה מסופרים ופילוסופים יהודים אשר הושפעו מהרעיונותיהם של הפילוסופים האירופיים מחד גיסא, ואת הרעיונות של ההשכלה מאידך גיסא. היהודים היו חיים בבידוד, ותחת השליטה של הרבנות (רבנים) שהייתה שליטה מוחלטת. כבר העבודה של הרבנות מאז ימי קדם להעלות רעיונות במוחם של היהודים בתור העם הנבחר, והם מעולים ועדיפים על בני אדם. הם כל כך מסתמכים על פסוקים מה
... Show MoreIraq is highly dependent on international markets to provide food for its residents. As imported food prices are highly dependent on crude oil prices in global markets, any shock in oil prices will have an impact on food consumption in the country. As a result, it is essential to study the demand for imported food at every time period. To the best of our knowledge as researchers, as not even a single study is available in the literature, this paper is considered the first to study the demand for imported food groups in Iraq. Therefore, the main objective of this research is to estimate demand elasticities for several imported food categories in Iraq. This study uses an Almost Ideal Demand System model to analyze the demand for imported f
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Highlights the role of taxes in being a major source of funding sources internal economic and social development, and then, any decrease in tax revenue caused by tax evasion, for example, would weaken the government's ability to finance their investments and core financing private sector investment as a result of reduced ability to increase their reserves's cash banks, as well as the weakening of the effectiveness of tax evasion taxes as a tool to guide economic activity in the framework of service for development, and to achieve justice. And the statement of the reasons for and methods of evasion mandated to pay the tax due on them, whether legitimately or illegal with the statement of the proposed methods to tackle tax evasion and elimina
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مشكلة البحث
وتعد مرحلة المراهقة من اصعب المراحل التي يمر بها الفرد واخطرها اذ يطلق عليها بمرحلة التفكير المجرد ، وهي مرحلة حاسمة في حياته اذ تتكون لديه معالم الشخصية .أنهم خزين الامة الحقيقي من الطاقات الحيوية التي لا تنضب لذا يجب الاهتمام بهذه الشريحة من المجتمع وتطويرهم وتوجيههم لاسلم الطرق للحفاظ على مستقبلهم ومستقبل الا
... Show MoreSteganography is a mean of hiding information within a more obvious form of
communication. It exploits the use of host data to hide a piece of information in such a way
that it is imperceptible to human observer. The major goals of effective Steganography are
High Embedding Capacity, Imperceptibility and Robustness. This paper introduces a scheme
for hiding secret images that could be as much as 25% of the host image data. The proposed
algorithm uses orthogonal discrete cosine transform for host image. A scaling factor (a) in
frequency domain controls the quality of the stego images. Experimented results of secret
image recovery after applying JPEG coding to the stego-images are included.