Background: This study was formulated to compare the effect of 5%hydrofluoric acid in comparison to 37%phosphoric acid with and without the application of silane on bond strength of composite to porcelain. Materials and Methods: Specimen preparation was divided in to two phases, metal-disks fabrication (8mm-diameter and 4mm-thickness) and ceramic veneering. Thirty two specimens were prepared, sandblasted with 50 μm aluminum oxide, and divided into four groups of eight samples. Groups I and III were etched with 37%phosphoric acid while groups II and IV were etched with 5%hydrofluoric acid; and groups I and II were silaneted while groups III and IV were not. Heliobond, and resin composite were applied to each specimen using a plastic transparent split mold (4mm- diameter and 4mm-height). Specimens were stored in distilled water for 24 hours then thermocycled for 100 cycles. Shear bond strength was determined by a Zwick universal machine at a cross-head speed 5 mm/minute. Results: Mean shear bond strength values were 21.02(group I), 23.31(group II), 4.00(group III), and 18.60(group IV). Paired-t revealed that specimens treated with 5%hydrofluoric acid were significantly higher than those treated with 37%phosphoric acid regardless the use of silane. The use of silane dramatically enhanced the bond strength of composite resin to porcelain for both acids. All specimens treated with 37%phosphoric acid without silane showed adhesive failure, while those treated with 5%hydrofluoric acid showed mostly cohesive failure within ceramic. Conclusion: Silane improved the shear bond strength of composite to ceramic, and hydrofluoric acid performed greater bond strength compared to phosphoric acid.
Environmental education is considered as process of getting Humans in communication with this environment and all its various resources. such process requires acquiring knowledge about the environment that com help humans understand their correlative relations with the environmental elements on one hand and among the environmental elements themselves on the other . Besides, such a process requires developing human skills that help them participate in developing environmental circumstances. Therefore environmental education is responsible for perspective and cultural development that governs human behavior. Regarding their environment and stimulating tendencies and interests towards the environment , let alone helping humans acquire the c
... Show MoreThe research aimed at identifying the level of Acute stress disorder and orientation towards supplication among the wives of the martyrs and knowledge of the two levels according to the age groups, academic achievement and profession. Sample of (72) wife of a martyr, and the results of the research indicated that the wives of the martyrs have symptoms of distress disorder and have adherence to the supplication to alleviate that disorder, as well as the results indicated that there are statistical differences in distress disturbance according to the variable of age groups, the profession variable and the variable of enrollment The academic year. As for the measure of the trend towards supplication, there are no statistical dif
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The attention of civil society organizations, governments and international non-governmental organizations in recent years has focused on the acute practices adopted by companies with the aim of reducing the tax burden, and the results of these practices have a negative impact on the tax revenues that the state uses to finance public needsThe aim of the research is to measure the impact of the voluntary disclosure of companies on tax planning for the period from 2011 to 2015 and the research community is in the General Tax Authority. The research sample is 6 companies within the private sector in the financial, banking, insurance and industrial fields. The research was based on a special model to measure the optional disclosure,
... Show MoreThis research sheds light on one of the important and vital topics for the banking sectors (technical requirements for the application of economic intelligence) namely by (Hardware, equipment, communication networks, software, databases). And the dimensions of the strategic success of the banks represented by(Customer satisfaction, customer trust, quality of service, growth) In the three Iraqi private banks, namely(Assyria International Investment, Mansour Investment, International Development Investment and Finance). Its implementation is an urgent necessity in order to improve the quality of its banking services to win the satisfaction of its customers and their confidence and then grow to achieve stra
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Three types of extracts ( aquatic, alcoholic, and oily ) were prepared from the fruits of coconuts, and a series of chemical tests were conducted in addition to the use of the FTIR equipment to determine the active locations in the prepared extracts. The results indicated the presence of active compounds (tannins, saponins, flavonoids, turbines and steroids) in the extracts prepared from the fruits of coconuts, also the antimicrobial capability of these extracts were tested on pathogenic bacteria isolated from wounds and burns infections cases. The results proved that the concentration 80 mg/ml of the aquatic extract is the minimum inhibitory concentration for the microbes: Proteus vulgaris and Pseudomonas fluorescence, while the
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Sports management is a fundamental pillar that supports sports institutions and plays a pivotal role in achieving advanced levels of success in talent development. The Talent Development Project is one of the key strategic initiatives of the Ministry of Youth and Sports. This study compares department heads with effective managerial competence to those with ineffective competence to highlight differences in performance quality. Through this comparison, the urgent need to assess the administrative performance skills of the heads of sports talent departments becomes evident, particularly their ability to lead and manage the Sports Talent Development Project. The objective is to identify strengths and weaknesses, establish a clear framework fo
... Show MoreThe purpose of this paper is to identify the statistical indicators of the searched variables and identify the relationship between the cognitive learning outcome and the performance of the two mastering skills by parallel spherical standing and equilibrium on the balance beam. And the identification of the percentage of the cognitive learning outcome contribution to the performance of the two mastering skills by parallel spherical standing and the equilibrium on the balance beam. The two researchers used the descriptive approach in the survey method and the correlational relations, being the most appropriate to the nature of the research problem. The research community for the second stage students in the College of Physical Education and
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