Background: The aim of this study was to measure the radiopacity (RO) of modified microhybrid composite resins by adding 2 types of nanofillers (Zinc Oxide and Calcium Carbonate) in two concentrations 3% and 5% and comparing them to unmodified microhybrid composite resins and to nanofilled composite resin. Materials and Methods: Two types of composite resin were used (Microhybrid composite MH Quadrent anterior shine and Nanofilled composite resin Filtek Z350 XT), for each tested group five disk-shaped specimens (1-mm-thick and 15 mm diameter) were fabricated. The material samples were radiographed together with the aluminum step wedge. The density of the specimens was determined with a transmission densitometer and was expressed in term of equivalent thickness of aluminum. Data analyzed by one-way ANOVA. Results: The radiopacity (RO) values of the tested group ranged between (0.9293- 2.6242 Eq. Al thickness) and there were significant differences among them. Nanofilled composite resin Filtek Z350 XT showed the highest value of RO while unmodified Microhybrid composite MH Quadrent anterior shine showed the lowest value of RO. Conclusion: The addition of 3% of both the ZnO and CaCO3 nanofillers fillers to microhybrid composite significantly increased the RO, while the addition of 5% of CaCO3 and ZnO nanofillers to microhybrid composite showed non-significant increase in the RO of the composite.
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
... Show MoreIn this study, experimental mortar combinations with 1% micro steel fibers, were examined to create geopolymer mortars. To test the effect of the fibers on the mortar's resistance, the geopolymer mortar was designed with various proportions of more environmentally friendly materials fly ash and slag. The percentage of fly ash by weight was 50, 60, and 70% of the slag. The best results were obtained when a 50:50 ratio of fly ash and slag were mixed with 1% micro steel fibers. The results showed that the mixtures containing fibers performed better in the considered tests (toughness index, ductility index, and resilience index). In the impact resistance test, the mixture contained 50% fly ash by weight of the slag with a temperature of
... Show MoreThe aim of this research is to employ the roundhouse strategy to study its impact on the students achievement of the 10th grade in physics and their core thinking. After the application of the research experience and gaining data, which was processed statistically using the statistical packages program (SPSS). The results of the researcher revealed the superiority of the students of the experimental group who studied using the roundhouse strategy on the students of the control group who studied the usual method in the achievement test. As results showed that there were statistically significant differences between the average scores of the experimental group and the average scores of the control group students in the core thinking test and
... Show MoreOne of the most important , compound which have active hydrogen is the compound possessing (thiol group) Biphenyl-4,4-dithiol is agood example utilized in a wide field for preparation mannich bases , avariety of new acetylenic mannich bases have been Synthesized and all proposed structure were Supported by FTIR , 1H – NMR, 13C-NMR , Elemental analysis and microbial study .