Dental amalgam is a mixture of approximately 50% mercury and varying ratios of silver, tin, zinc, and copper. Dental amalgam is a major source of mercury pollution because it is readily absorbed through 90-100% vapour and the oral mucosa. In addition, in certain situations with the oral environment, various types of metallic orthodontic brackets are highly aggressive and can lead to corrosion. However, polyvinyl alcohol (PVA) material has no cytogenetic effects on human health or the environment and is therefore applied in the manufacturing of the new composite material. Different additives from the bonding agent (PVA; 2.4, 4.8, and 7.2 g) dissolved in about 10 ml of water, heated on a hot plate under a hig
... Show MoreSeven Zn-dithiocarbamate complexes were suggested as corrosion inhibitors. Density functional theory (DFT) was used to predict the ability of inhibition. Room temperature conditions were applied to suggest the optimization of complexes, physical properties, and corrosion parameters. In addition, the HOMO, LUMO, dipole moment, energy gap, and other parameters were used to compare the inhibitors efficiency. Gaussian 09 software with LanL2DZ basis set was used. Total electron density (TED) and electrostatic surface potential (ESP) were utilized to show the sites of adsorption according to electron density.
A series of 1,3-diarylprop-2-en-1-one oximes (7-12) were synthesized via reaction of 1,3-diarylprop-2-en-1-one (1-6) with NH2OH. HCl in dry pyridine. In order to produce the required products (13-18) as anti-isomers, these products (7–12) were then treated with acetic anhydride in dry pyridine. Different substitutes are maintained, resulting in the separation of different products in different yields The recently produced esters are thought to be useful as building blocks for the synthesis of substituted pyridines and many other nitrogen-holding complexes, which are elaborate structures in medicinal chemistry and present in a variety of pharmaceutical medications. The synthesized products were characteriz
... Show MoreGovernmental establishments are maintaining historical data for job applicants for future analysis of predication, improvement of benefits, profits, and development of organizations and institutions. In e-government, a decision can be made about job seekers after mining in their information that will lead to a beneficial insight. This paper proposes the development and implementation of an applicant's appropriate job prediction system to suit his or her skills using web content classification algorithms (Logit Boost, j48, PART, Hoeffding Tree, Naive Bayes). Furthermore, the results of the classification algorithms are compared based on data sets called "job classification data" sets. Experimental results indicate
... Show MoreBackground: The aims of this study were to evaluate the effect of implant site preparation in low-density bone using osseodensification method in terms of implant stability changes during the osseous healing period and peri-implant bone density using CBCT. Material and methods: This prospective observational clinical study included 24 patients who received 46 dental implants that were installed in low-density bone using the osseodensification method. CBCT was used to measure the bone density pre- and postoperatively and implant stability was measured using Periotest® immediately after implant insertion and then after 6 weeks and 12 weeks postoperatively. The data were analyzed using paired t-test and the probability value <0.05 was conside
... Show MoreCopper (I) complex containing folic acid ligand was prepared and characterized on the basis of metal analyses, UV-VIS, FTIR spectroscopies and magnetic susceptibility. The density functional theory (DFT) as molecular modeling calculations was used to determine the donor atoms of folic acid ligand which appear clearly at oxygen atoms binding to hydrogen. Detection of donation sights is supported by theoretical parameters such as geometry, mulliken population, mulliken charge and HOMO-LUMO gap obtained by DFT calculations.
An experimental investigation has been made to study the influence of using v-corrugated aluminum fin on heat transfer coefficient and heat dissipation in a heat sink. The geometry of fin is changed to investigate their performance. 27 circular perforations with 1 cm diameter were made. The holes designed into two ways, inline arrangement and staggered in the corrugated edges arrangement. The experiments were done in enclosure space under natural convection. Three different voltages supplied to the heat sink to study their effects on the fins performance. All the studied cases are compared with v-corrugated smooth solid fin. Each experiment was repeated two times to reduce the error and the data recorded after reaching t
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