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 problem of the study was to identify the possibility of benefiting from the application of the target cost system as a modern cost system to activate the environmental cost management instead of the traditional systems used in the company due to the great transformations witnessed by the business environment in all fields, which have resulted in the search for modern systems to provide more accurate and more appropriate information to reduce Costs, because accurate information makes the company have a complete vision to achieve the company’s goals. To solve this problem, the research was based on the following hypothesis (that the role of the target cost system leads to the activation of environmental cost management). Target c
... Show MoreSamuel Beckett’s Happy Days (1961) clearly portrays a lack of communication among the characters of the play which refers to the condition of modern man. This failure of communication led Samuel Beckett to use a lot of pauses and silences in all plays written instead of using words. To express the bewilderment of the modern man during the 20th century, Beckett adopts the use of no language strategy in the dramatic works. After World War II, people were without hope, religion, food, jobs, homes, or even countries. Beckett gave them a voice. He used a dramatic language out of everyday things, in which silence was part of the syntax as a poetic repetition. Language is no more important to the modern man; instead, he us
... Show MoreDuring the 1970s, communicative view of language teaching began to be incorporated into syllabus design. The central question for the proponents of this view was: what does the learner want/need to do with the target language? This lead to the emergence of a teaching method (or approach) called communicative language teaching (CLT) during the late 1970s and early 1980s focusing on the functions that must be incorporated into a classroom. According to Brown (2001:43) CLT is a unified but broadly based, theoretically well informed set of tenets about the nature of language and of language learning and teaching. Harmer (2001:84) states that the communicative approach is the name which was given to a set of beliefs which included not only a
... Show MoreThe mass collision energy loss (dE/dX), the mass radiative energy loss (Srad/) and the total mass stopping power of electrons in the energy range of 0.01 MeV up to 1000 MeV has been calculated for Lung, Urea and Skin. The results of the present work for the mass collision stopping power of electrons in Lung, Urea and Skin are in excellent agreement with the standard results given by ESTAR program, where the maximum percentage error between the present calculated values and that of ESTAR program in Lung tissue, Urea and Skin tissue is 0.27%, 0.3% and 0.8% respectively. The mass radiative energy loss of electrons in the same energy range is also calculated using a modified equation, and the results are found to be in very good agreem
... Show MoreObjectivity is the common denominator between the qualities and elements of a news story that is described as the mother of journalistic arts. When there is doubt about the authenticity of the information contained in the press, whether readable, audible or visual, it means that there is an imbalance in objectivity. When, furthermore, there is an incorrect and intentional use of words in order to influence readers, it means to move away from objectivity as a necessary element in the success of the media institution; and the success of its editorial material.
But the objective interpretation may take several dimensions to the liaison. For the purpose of grasping the interpretation of objectivity among those liaisons working in the
... Show MoreAbstract
The Purpose of This Research is The Main Factors In out Comes Phenomena From Primary School Which in Creased in Lost Period in Iraq And to Find Solutions to The This Problem.
In Order to Achieve Al The Aim The Research Choose a Systematic Random Sample of School Records For Students in Some Primary Schools in Karkh and Rusafa and Year of Study (2010-2015) and Size (40) Samples, included (16) Variable , Collected in Form Prepared by The Research As a Way to Analyze The Data.
Remember to Summarize The (6) Main components Pay a Student to Drop out of Primary Schools in The Province of Baghdad are Arranged As Follows:
... Show MoreAim of the Study: The paper aims at identifying the extent of the role of strategic leadership represented by its four dimensions (administrative, transformational, political, moral) in fulfilling the requirements of university governance (Context, message and Goal, Management orientation, Independence, Issue, Sharing)
Methodology: A survey is applied to (107) members of the teaching staff at the college of Administration and Economics/ University of Mosul. To achieve the goals of the study, the researcher makes use of a number of tools such as: questionnaire, statistical tools and methods (repetitions, perce
... Show MoreObjectives: This study explored knowledge, attitude, and practice of infection control by dental students at College of Dentistry/ University of Baghdad, Iraq. Material and Methods: Three hundred dental students participated in this study. A self administrated questionnaire with 21 close ended questions related to use of personal protective equipments, infection control awareness, vaccination status, percutaneous exposures, and attitude towards treatment of patients with hepatitis B (HBV)/ or human immunodeficiency virus (HIV) was distributed to dental students. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 21. Fisher exact and Chi-square test were used with significance level set to 0.05. Results: The
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