Background: Poly (methylmethacrylate) is not ideal in every aspect and has disadvantages such as insufficient surface hardness, increase water sorption and poor impact resistance and the latter being the primary cause of fracture of denture base resins. The aim of this study was to evaluate the effect of addition of silanized nano- hydroxyapatite (HA) on some properties of heat cured acrylic denture base material. Materials and methods: HA nano particles were first silanized with ï§MPS (tri methacryloxypropyletrimethoxy silane coupling agent) then ultrasonicated with methylmethacrylate (monomer) to disperse agglomerated nano particles and mixed with polymer. 2% by wt of HA nano particles was selected as the best concentration that added to the denture base material according to the pilot study.(100) specimens were prepared by conventional water bath processing technique and divided to two groups: 50 specimens for control group or 0% HA and 50 for experimental group or 2% HA then each group was subdivided to five groups with 10 specimens for each test: impact strength, transverse strength, surface hardness, surface roughness, water sorption and water solubility. Results: highly significant increase in impact strength and surface hardness after addition of 2% HA nano particles but not significant decrease in water sorption whereas solubility was significantly decreased. Surface roughness was significantly increased as compared with control group but remained within the acceptable limit less than 2ïm. HA nanoparticles addition highly decreased the transverse strength value. Conclusion The addition of 2% HA nano particles considerably improved the impact strength, surface hardness and had positive effect on water sorption and solubility. Whereas the same concentration tend to highly decreased transverse strength and increase surface roughness.
In this study, the stress-strength model R = P(Y < X < Z) is discussed as an important parts of reliability system by assuming that the random variables follow Invers Rayleigh Distribution. Some traditional estimation methods are used to estimate the parameters namely; Maximum Likelihood, Moment method, and Uniformly Minimum Variance Unbiased estimator and Shrinkage estimator using three types of shrinkage weight factors. As well as, Monte Carlo simulation are used to compare the estimation methods based on mean squared error criteria.
Change the morphological characteristics with the change of the factors affecting it has been shown that the Tigris River has the characteristics of the morphology of the low values in terms of depth, width and perimeter wet and gradient which in turn affected the morphological and other characteristics in terms of the direction and pattern of runoff came through the study of 48 cross-section is taken of the Tigris River Year 2008 by section for each 1 km, it has been shown that the average width of the Tigris River does not exceed 221.1 meters and the average depth of 3.9 meters either wet ocean amounted to 268.9 meters and changed the cross-section area of the last section at a rate of 4594.3 square meters, and through the study turned
... Show Morethe study aimed to identify the impact of the types of cooking utensils in transition metal elements to food and the effect of acid and storage in the concentration of these elements. used five types of cooking utensils including aluminum. tefal, astainls steel, glass. (pyrex), and ceramic prepared in it the food meal. the same meals were repeated add to them acid. the estimate of mineral elements in the meal prepared before storage and after storage in refrigerator temperature degree. the result shows the increase of aluminum concentration in the meals that prepared in aluminum pot reaching 2.913 pmm while reached less concentration in the meal prepared in astainls pot reaching 0.325 pmm. the highest concentration of iron reached 25.2 p
... Show MoreNew mixed ligand complexes of New Schiff base 4,4'- ((naphthalen-1-ylimino) methylene) dibenzene-1,3-diol and 8-hydroxy quinoline: Synthesis, Spectral Characterization, Thermal studies and Biological Activities
An abstract is a brief summary of a research article, thesis, Schiff base ligand (L) was prepared by the reaction of 4-aminantipyrine with o-phenylenediamine, the prepared ligand characterized by Micro elemental Analysis, FT. IR, UV-Vis, and 1H,13C-NMR spectroscopy.complexes of Mn(II), Co(II), Ni(II), Cu(II) and Hg(II) with Schiff base and 1,10-phenanthroline (Phen) have been investigated in aqueous ethanol with (1:1:1) (M:L:Phen). The prepared complexes were characterized using flame atomic absorption, (C. H. N) Analysis, FT. IR and UV-Vis spectroscopic methods as well as magnetic susceptibility and conductivity measurements. From the obtained data the octahedral structure was suggested for all complexes. The biological screening effects o
... Show MoreEnticed by the present scenario of infectious diseases, four new Co(II), Ni(II), Cu(II), and Cd(II) complexes of Schiff base ligand were synthesized from 6,6′-((1E-1′E)(phenazine-2,3-dielbis(azanylidene)-bis-(methanylidene)-bis-(3-(diethylamino)phenol)) (
The present study aimed to determine the genetic divergence of seven maize genotypes (Al-Maha, Sumer, Al-Fajr, Baghdad, 5018, 4 × 1 single hybrid, and 4 × 2 single hybrid) under two varied levels of nitrogen fertilization (92 and 276 kg N ha-1). The experiment occurred in 2022 in a randomized complete block design (RCBD) with a split-plot arrangement and three replications at the College of Agricultural Engineering Sciences, University of Baghdad, Iraq. The nitrogen fertilization levels served as main plots, with the maize genotypes allocated as the subplots. The results revealed that genetic variance was higher than the environmental variance for most traits, and the coefficient of phenotypic variation was close to the genetic va
... Show MoreThe expenditures of the general budget, in its operational and investment divisions, are a basic factor in the economic and social growth of any country, and its impact on various economic activities such as income, employees , and the standard of living of members of society. This was based on a basic premise: Does increasing or decreasing investment expenditures have an effect on increasing or decreasing the tax proceeds, What is the level of relationship between them? and to achieve the goal of the research, an inductive and analytical method was chosen to measure the impact of the investment budget expenditures on the tax outcome quantitatively using the financial data obtained from The General Authority for Taxes, Ministry of Financ
... Show More