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.
Abstract
One of the major components in an automobile engine is the throttle valve part. It is used to keep up with emissions and fuel efficiency low. Design a control system to the throttle valve is newly common requirement trend in automotive technology. The non-smoothness nonlinearity in throttle valve model are due to the friction model and the nonlinear spring, the uncertainty in system parameters and non-satisfying the matching condition are the main obstacles when designing a throttle plate controller.
In this work, the theory of the Integral Sliding Mode Control (ISMC) is utilized to design a robust controller for the Electronic Throttle Valve (ETV) system. From the first in
... Show Moreيدرس هذا البحث مشكلة اعتماد الجمهور العراقي على الصحف، باعتبارها إحدى وسائل الإعلام التقليدية، في تكوين معلوماته ومعرفته العامة. وهي دراسة وصفية اعتمدت المنهج الوصفي المسحي الذي يصور الظروف أو الاتجاهات الحالية للظاهرة قيد الدراسة ويحاول تفسيرها. استخدم الباحث الاستبانة في المقام الأول كأداة بحث، حيث تم تصميمها وتوزيعها على عينة مكونة من 150 باحثا قصديا من قراء وقراء الصحف. وينتهي الباحث بالنتائج التالية: إ
... Show MoreTelevision white spaces (TVWSs) refer to the unused part of the spectrum under the very high frequency (VHF) and ultra-high frequency (UHF) bands. TVWS are frequencies under licenced primary users (PUs) that are not being used and are available for secondary users (SUs). There are several ways of implementing TVWS in communications, one of which is the use of TVWS database (TVWSDB). The primary purpose of TVWSDB is to protect PUs from interference with SUs. There are several geolocation databases available for this purpose. However, it is unclear if those databases have the prediction feature that gives TVWSDB the capability of decreasing the number of inquiries from SUs. With this in mind, the authors present a reinforcement learning-ba
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Current research aims to know the personality traits of gifted
and has been the preparation , students in the Hashemite Kingdom of Jordan
pedagogy of talented ) 60 ( views of a sample of of the search tool of the
And has been applied to the . items ) 52 ( formed from the search tool , teachers
sample, and after treatment results reached statistical research results and the
researcher presented a number of recommendations including:
: Recommendations
1. Need for the development and rehabilitation of mentally gifted and structure
their characters in line and mental abilities and knowledge.
ams and psychological guidance for personal Preparation of scientific progr . 2
. development for the gifted
3. Work to
Сатья посвящена выделению и описанию функциональных стилей русского языка. В работе будет предствлена стилистическая характеристика заимствованной лексики, которая в некоторых случаях заменяет собственно русские слова, что может приводить к затемнению смысла высказывания, эвфемизации его, кроме того, заимствования заполняют определенные стилистические книши, образовавшиеся в связи со структурны
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Mosques could be considered as one of the most powerful architectural types throughout historical ages. With their highly symbolic formal legacy, Mosques play an essential role in providing the Islamic city with its special identity. Nevertheless, the advent of digital technology and its ubiquity at different levels of architectural design marked the emergence of new tendencies in the Architecture of Mosques, represented by various models added to the storage of this architectural type. Consequently a review of these tendencies would be needed, aiming at pointing out the formal transformations and new suggested characteristics.
The paper investigates the surviving and the disappearing formal components of&n
... Show MoreThe primary objective of this study was to identify the obstacles and problems encountered in the work of sports clubs according to the reality of the application of administrative automation. The present study was conducted in the sports club headquarters of Baghdad within the timeframe of October 2021 to December 2021. In the present study, a descriptive approach was used by the researchers in an analytical style according to the nature of the problem to be studied. The research community of the current study was composed of 100 sports clubs in the governorate of Baghdad. A total of 80 questionnaires were filled by the sample participants, who represented a percentage of 80% of the research community. After processin
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Objective: The present study aimed to evaluate the occupational health hazards that face health care providers in Sulaimani City.
Methods: A cross-sectional study conducted utilizing quantitative data collection methods. It involved 159 respondents including Physicians, Pharmacists, Medical assistants, Laboratory Instructors and Nurses who worked in 8 major health facilities in Sulaimani city, Kurdistan region, Iraq.
Results: Nurses were the most susceptible group to sharp related injuries 13.84%, cuts and wounds 10.69% than the others and they were more experiencing verbal abuse in the workplace 15%. Laboratory instructors represent the most exposed group
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This research deals with what so called concept of The Human Model and how Iraqi Media concerns of this concept practically as it plays a key role in attracting readers, on the first hand. On the second, it is important to shed light on the scientific desire of the Iraqi Media and how it deals with this contemporary trend especially in editorial media.
The importance of the research stems from the fact that it alerts to a new stream of modern trends in journalistic writing, according to many modern Arab and foreign media studies; and to the importance of employing human modeling in dealing with facts, events, issues and problems in various editorial arts within their effective influence in concilia
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The majority of the arts share a goal directed at employing art works for the purpose of conveying the intellectual and symbolic connotations in order to work on a directed message and to achieve expression and aesthetic, and highlights the cinematographic mediator who shares with the other media in the use of intellectual properties through its tools and works. Consciousness and establishment of multiple visions with different views to reveal the intellectual, aesthetic and expressive devices located opposite the advertiser to perform functions with goals that intellectually deduce, insights and ideas emerging within the general context of the drama narrative and highlights among the discourse operators the cinematographer, And t
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