Background: The purpose of this study was to evaluate the effect of addition of surface treated silicon dioxide Nano filler (SiO2) on some properties of heat cured acrylic resin denture base material (PMMA). The properties were impact strength, transvers strength, and surface hardness. Materials and methods: In addition to controlled group SiO2 powder was added to PMMA powder by weight in three different percentages 3%, 5% and 7%, mixed by probe ultra-sonication machine.120 specimens were constructed and divided into 3 groups according to the test (each group consist of 40 specimens) and each group was subdivided into 4 sub-groups according to the percentage of added SiO2 (finally each subgroup consist of 10 specimens). The tests conducted were impact strength (charpy test), transverse strength and indentation hardness (shore D). Results: A highly significant increase in impact strength and transverse strength was observed with the addition of SiO2 powder to (PMMA) at the percentage of 3% and 5%; while a significant reduction occurred in both impact and transverse strength specimen’s tests at the percentage of 7% A Highly significant increase in surface hardness was observed at the percentage of 3%, 5%and7. Conclusion: The addition of Nano SiO2 powder to acrylic resin improves the impact strength and transverse strength of acrylic resin at the same time this addition increase surface hardness with the increase in the concentration of Nano SiO2 particles.
Praise be to God, Lord of the worlds, and prayers and peace be upon our master Muhammad and upon his family and companions.
And after:
Muslim scholars have fought in the extent of regard to these interests, each according to his opinion and according to his evaluation, and his consideration of this interest, but it remains important that the legislation in them needs more precaution and caution against the predominance of passions, because the passions often decorate spoilers so they see an interest, so practical application must To realize the spirit of Islamic Sharia in its entirety of its rulings, and the preponderance between the interests and evils that prevail in our societies, which c
... Show MoreJudaism followed the approach of monotheism after God Almighty sent Moses (peace be upon him) to convey to them the messages of their Lord, so that they might be on a right guidance and path, but the people did not follow that path.” Love of matter and faith in what is witnessed, so they portrayed the Lord in several images in line with what their souls drew upon them.
The achievement of world peace is a humanitarian demand that humanity has sought since its existence. Despite the international and regional efforts to achieve this demand, it is still reaching its desired ambitions if conflicts, contradictions, and internal and external wars continue to justify us clearly in terms of ethnic, religious and sectarian conflict. The revolution of informatics and the impact of globalization opened a new era of communication and openness and the negative and positive impact of others, which re-published and distributed values, ideas and new cultures Some of them carries extremist ideas urging violence and destruction and other abolition, it became necessary to follow policies and reward The culture of peace,
... Show MoreAbstract
Experimental work from Magnetic Abrasive Finishing (MAF) tests was carried out design parameters (amplitude, and number of cycle which are formed the shape of electromagnetic pole), and technological parameters (current, cutting speed, working gap, and finishing time) all have an influence on the mechanical properties of the surface layer in MAF process. This research has made to study the effect of design and technological parameters on the surface roughness (Ra), micro hardness (Hv) and material removal (MR) in working zone. A set of experimental tests has been planned using response surface methodology according to Taguchi matrix (36) with three levels and six factors
... Show MoreCultured fruits of theCorundum Coriandrum sativum were sown On 11/11 / 2008 in basins containing 15 kg of soil (Silty Loam) .Fruits were divided into two parts the first was soaked in normanl water and the second was magnetized for a period of 24 hours Irrigation was up to (75% of capacity field.Two types of water (normal water and magnetized water)with three repetitions were used the access to magnetic water was supplied from a special electric device. Recorded measurements were plant height the number of stems / plant, weight of plant, number of flowers, 1000 seed weight) during the cultivation period, which ended on 11/5/2009. Results indicated the absence of any effect of magnetic water on plant growth of Fenugreek while seeds tre
... Show MoreThe research dealt with the effect of Kut Barrage on the geomorphological processes and the natural environment system in the course of the Tigris between the cities of Al-Ahrar and Kut in central Iraq. It was clear from the research the contribution of Kut Barrage in changing the surface runoff system between the front and back of the barrage, as well as changing the type of processes and the prevailing geomorphic forms, as the sedimentation activates the front of the barrage and erosion at its back, which affected the change in the morphology of the river, sediment retention at the front of the barrage, the burial of the bottom and reducing the validity of the stream. This also affects the efficiency of the barrage’s work and coastal er
... Show MoreA discussion about the repercussions of the exchange rate on the behavior of stock markets became one of the basic principles of financial economics. The Istanbul Stock Exchange , considered one of the fastest financial markets growing in the region, driven by solid economic activity, for a diversified economy which classified as one of the the fastest growing economies in the world. However, the aforementioned market witnessed sharp fluctuations in the past few months, coinciding with the continuous fluctuations in the exchange rate of the Turkish lira, posing a serious challenge to the economic and investment environment in a c
... Show Moreيهدف البحث إلى التعرف على The research aims to identify the effect ofاثر التركيب العمري للسكان على الناتج المحلي الإجمالي في العراق وتحديد الفئات العمرية من أطفال ومنتجين أي من هم في سن العمل والمسنين لأهمية ذلك لإغراض التخطيط الاقتصادي.إنeffectofeee age structure of the population on GDP in Iraq and determine the age groups of children and any of the producers wham are of working age and the elderly of the importance for the purposes of economic planning. نسبة الفئة العمرية Proportion of the age group (00- -4 4سنوات اقتربت من
... Show MoreService companies always working to increase their competitiveness and efficiency of the survival, growth and development in the present and the future, including insurance companies, so as to increase competition, especially after the emergence of the civil companies dramatically after 2003, has become the goal of recent studies carried out by the organizations is the human capital, because its success and excellence and achievement its objectives depends on the human, and this does not mean that the other components are not important, but also rely on the rights which has increased interest in the search for the way in which they can guide the behaviors and values and their own language in line with the organization's strategy an
... Show More