Background: Polymethyl methacrylate (PMMA) is the most commonly used material in denture fabrication. The material is far from ideal in fulfilling the mechanical requirements. Midline fracture; poor thermal conductivity and water sorption, are common problem in this material. The purpose of this study was to evaluate the effect of addition of surface treated Aluminum oxide nano fillers on some properties of heat cured (PMMA). Materials and methods: In addition to controlled group of heat cured PMMA the silanized (Al2O3) nanoparticles was added to PMMA powder by weight in three different percentages 1wt%, 2wt% and 3wt%, mixed by probe ultra-sonication machine. 200 specimens were constructed and divided into 5 groups according to the test (each group consist of 40 specimens) and each group was subdivided into 4 sub-groups. The tests conducted were thermal conductivity, thermal diffusivity, transverse strength, indentation hardness (shore D), surface roughness, water sorption and solubility. The results were statistically analyzed using ANOVA and Dunntt t-test. Results: A highly significant increase in transverse strength was observed with the addition of (Al2O3) nanoparticles to (PMMA) at the percentage of 1wt%, the value was 117.72 Mpa and significant increase at 2wt%; while a significant reduction occurred in transverse strength at the percentage of 3% the value was 90.110 Mpa. A significant increase in surface hardness and non significant differences in surface roughness were observed for all percentages. Conclusion: The addition of Al2O3 nanoparticles to acrylic resin improves the thermal properties and transverse strength of acrylic resin at the same time this addition decreases water sorption and solubility.
The central nervous system is the most important system and is very sensitive to any accidental infection during ontogenesis; it includes brain and spinal cord. The cerebellum is the second largest part of the brain after cerebrum and it’s very sensitive to the abnormal changes during the embryological development. This study was designed to investigate the effect of the maternal exposure of selected concentrations of suspension of nanoparticles on the ontogenesis of the rat cerebellum after embryos implanted in uterus. A total of 60 female pregnant rats were divided in to three groups, each contains 20 females. Group1 (G1) was treated orally with 2mg/kg /body weight (b. wt) of suspension of silver nanoparticles (Ag NPs). While group 2 (G
... Show MoreThis research aims to identify how organizational compatibility, which represents the independent variable, affects higher performance, which is considered a dependent variable, given the importance of these variables in industrial organizations and their clear impact on their stability, survival, and growth in the light of changing environmental challenges. Where the practical research problem was represented by the weakness of awareness of the importance toward organizational compatibility and its dimensions (organizational loyalty, organizational similarity, affiliation or membership, compatibility with goals, and compatibility with values), which is meant by the individual's compatibility with the organization in which he/she w
... Show MoreArab-Islamic architecture has undergone a change at multiple levels affected by modern technology, so the research sought to address the role of contemporary technologies on a fundamental and fundamental component of architecture, which is the architectural space, what is known as the essence of architecture and its ultimate destination, with a focus on the architectural space in the architecture of the contemporary Arab Islamic mosque, because the mosque’s architecture is so important in Islamic law and the belief of the Muslim person himself, where the mosque is the functional style produced by the Islamic faith and embodied in it, whereas, knowing the levels of influence of contemporary technologies in the architectural spac
... Show MoreThis paper aims to investigate the flexural behavior of reinforced concrete beams considering fire resistance by adding Lightweight Expanded Clay Aggregates (LECA) to the concrete mix as partial coarse aggregate replacement. LECA is a type of porous clay with a uniform pore structure with fine, closed cells and hard, tightly sintered skin. The experimental work comprised four reinforced self-compacted concrete beams. All the specimens were identical in their geometrical layout of 1600×240×200 mm, reinforcement details, and support condition (simply supported). For all the beams, the main reinforcement was provided by two bars, each having a diameter of 12 mm, while a bar of 6 mm diameter was employed for the top and shear reinforc
... Show MoreSilver diamine fluoride (SDF) has shown effectiveness in hardening tooth structure and killing bacteria. Therefore, it can be used to prevent and arrest dental caries. Riva Star (SDF) treatment alone will stop cavities but will not reverse the cavitation. The Silver Modified Atraumatic Procedure, often known as Smart, is the optimum technique for regaining the tooth's structure and function. Glass ionomer was introduced in (1972) as a new material that has become one of the most widely used materials in restorative dentistry. By releasing fluoride ions, this material has a therapeutic impact on the surrounding tooth structure. Microleakage is the ingress of bacteria, its byproducts, toxins, chemicals, oral fluids, and ions between t
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The research aims to build an integrated frame of knowledge for the basic research topics, represented by (assimilation of knowledge, strategic clarity) and their basic variables, by examining the most important scientific propositions on these topics in administrative thought, and framing the knowledge contained in them, in a serious attempt to provide appropriate answers to questions The research dilemma, and the research was applied in the Iraqi Airways Company, whose number is (1200) employees, and the descriptive and analytical approach was adopted in conducting the research. A valid form for statistical analysis, i.e., with a retrieval rate of (92%). The two researchers used the (SPSS & AMOS) program for
... Show MoreThe current research aims to identify (the effect of CORT program on creative thinking for middle school students in the art education history of ancient art subject).
The research society continue of the5th of scientific students in ALsadreen secondary school of excellence which related of the Directorate of Education al-sader city, for the academic year (2015/2016), The sample was (35) students for each of the two groups (experimental and control). The equivalence between the research groups was carried out in the IQ variable, the age and the level of the father and mother.
The researcher used the experimental method of partial control and the post-test. If the course of
... Show MoreWhen optimizing the performance of neural network-based chatbots, determining the optimizer is one of the most important aspects. Optimizers primarily control the adjustment of model parameters such as weight and bias to minimize a loss function during training. Adaptive optimizers such as ADAM have become a standard choice and are widely used for their invariant parameter updates' magnitudes concerning gradient scale variations, but often pose generalization problems. Alternatively, Stochastic Gradient Descent (SGD) with Momentum and the extension of ADAM, the ADAMW, offers several advantages. This study aims to compare and examine the effects of these optimizers on the chatbot CST dataset. The effectiveness of each optimizer is evaluat
... Show MoreHigh intraocular pressure (IOP) is a recognized risk factor for glaucoma and optic nerve injury, and it is one of the primary causes of vision loss globally. Anabasis articulata (AA) is a desert plant found in Iraq. The extract of AA is used to cure diabetes, fever, eczema, and kidney infections. The aim of the study is to evaluate the antioxidant effect of methanol extract of AA on intraocular pressure in the glaucoma rat model. Forty-two rats were allocated into seven groups, each with six animals:: group 1 (normal), group 2 (control), in which animals were induced to have elevated IOP by betamethasone suspension injection, groups 3,4 and 5 for evaluating the effect of 50,100 and 150 mg/kg/day of the tested extract, respective
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