Background: This study aimed to evaluate the effect addition of polyester fibers on the some mechanical properties of heat cured acrylic resin (implant strength, flexural strength and hardness) Materials and methods: Ninety specimens were used in the study. Thirty specimens were used for impact strength measurements (80mm X 10mm X 4mm) length, width and thickness respectively. The specimens divided into three test groups (n=10), first group formed from heat cure acrylic resin without fiber reinforcement. Second group was formed from heat cure acrylic resin was reinforced with 2 mm length polyester fiber and third group was formed from heat cure acrylic resin reinforced with 4mm length polyester fiber, impact strength measured by impact testing device. 30 specimens with (65 mm X 10mm 2.5mm) length, width and thickness respectively were used in 3 groups (n=10) flexural strength test. The flexural strength was measured by using flexural testing device. 30 specimens with (65mm X 10m X 2.5mm) length width and thickness respectively were used for hardness test. The specimens were divided into 3 group (n=10) as in impact strength and flexural strength. Hardness measured by using (shore D hardness tester TH210). Results: revealed statistically significant increase on impact strength especially on 4mm length when compared to control group. Significant decreases in flexural strength of PMMP. When compared to control group with 4mm length fiber reinforcement. Non significant decrease when compared control group with 2mm length fiber reinforced PMMA. Significant decrease in hardness of PMMA resin after reinforcement with 2mm, 4mm lengths polyester fibers. Conclusions: Strengthening with the polyester fiber decreased the flexural strength and hardness of the resin, but increased impact strength. Thus when high impact acrylic resins are needed, fiber reinforced resins may be the material of choice.
It is believed that culture plays an important role in the ELF classroom activities (Al- Mutawa, & Kilani, 1989:87). It is important for the teacher to recognize potential negative (culturally based) perceptions of their learners. In Iraq, for instance, it is not. Uncommon to meet silent expressionless students that arc supposedly English language learners. It is possible for the beginner to interpret this negatively as a lack of interest in the study of English. This interpretation may play a harmful role in the classroom methodology. An instructor has to be intercultural competent to be an effective teacher. It will be more effective if the instructor adopts a consistent style of instruction to allow learners to adapt within the bounds of
... Show MoreAs a marker of systemic inflammation, raised (C-reactive protein (CRP)) concentrations which are still within the normal range have been associated with an increased inflammation of chronic renal diseases (CRD). The current study aimed to establish potential determinats of raised CRP concentrations in patients who treated in Heamodialysis room,then study the relationship between CRP& some biochemical parameters related CRD We used a CRP latex reagents Kit which is based on an immunological reaction between CRP antisera bounded to the biologically inert latex particles or with CRP in the test specimens of 19 patients with (CRD) mean age 48 years ,range = 30?65 & in 21 healthy subjects as control group their age range = 30 ?45 years. The
... Show MoreA total of 70 pregnant women with toxoplasmosis were studied to evaluate of some immunological aspects. The women were distributed into three groups: 37 women were IgG positive, 18 women were IgM positive and 15 women were IgG and IgM positive as well as 25 healthy women were considered as control group. Serum samples were collected and ELISA method was employed to assess levels of interleukins 4, 6, 10, Interferon gamma-induced protein 10 (IP-10), Granulocyte-macrophage colony-stimulating factor (GM-CSF) and Vascular endothelial growth factor (VEGF). As compared with control the levels of cytokines were significantly increased in serum of three pregnant women groups with toxoplasmosis and the highest increase was observed in the IgM positi
... Show MoreBackground: Radiopacity is one of the prerequisites for dental materials, especially for composite restorations. It's essential for easy detection of secondary dental caries as well as observation of the radiographic interface between the materials and tooth structure. The aim of this study to assess the difference in radiopacity of different resin composites using a digital x-ray system. Materials and methods: Ten specimens (6mm diameter and 1mm thickness) of three types of composite resins (Evetric, Estelite Sigma Quick,and G-aenial) were fabricated using Teflon mold. The radiopacity was assessed using dental radiography equipment in combination with a phosphor plate digital system and a grey scale value aluminum step wedge with thickness
... Show MoreBackground: Radiopacity is one of the prerequisites for dental materials, especially for composite restorations. It's essential for easy detection of secondary dental caries as well as observation of the radiographic interface between the materials and tooth structure. The aim of this study to assess the difference in radiopacity of different resin composites using a digital x-ray system. Materials and methods: Ten specimens (6mm diameter and 1mm thickness) of three types of composite resins (Evetric, Estelite Sigma Quick,and G-aenial) were fabricated using Teflon mold. The radiopacity was assessed using dental radiography equipment in combination with a phosphor plate digital system and a grey scale value aluminum step wedge with thickness
... Show MoreLow conversion copolymerization of N-vinyl-2-pyrrolidon M.W = (111.14) VP (monomer-1) has been conducted with acrylic acid AA and methymethacrylate MMA in ethanol at 70ºC , using Benzoyl peroxide BPO as initiator . The copolymer composition has been determined by elemental analysis. The monomer reactivity ratios have been calculated by the Kelen-Tudos and Finman-Ross graphical procedures . The derived reactivity ratios (r1 , r2 ) are : (0.51 , 4.85) for (VP / AA ) systems and (0.34 , 7.58) for (VP , MMA) systems , and found the reactivity ratios of the monomer AA , MMA is mor than the monomer VP in the copolymerization of (VP / AA) and (VP /MMA) systems respectly . The reactivity ratios values were used for microstructures calculation.
Although renewable energy systems have become an interesting global issue, it is not continuous either daily or seasonally. Latent heat energy storage (LHES) is one of the suitable solutions for this problem. LHES becomes a basic element in renewable energy systems. LHES compensate for the energy lack when these systems are at low production conditions. The present work considered a shell and tube LHES for numerical investigation of the tube rotation influence on the melting process. The simulation and calculations were carried out using ANSYS Fluent software. Paraffin wax represents the phase change material (PCM) in this work, while water was selected to be the heat transfer fluid (HTF). The calculations were carried o
... Show MoreThis investigation presents an experimental and analytical study on the behavior of reinforced concrete deep beams before and after repair. The original beams were first loaded under two points load up to failure, then, repaired by epoxy resin and tested again. Three of the test beams contains shear reinforcement and the other two beams have no shear reinforcement. The main variable in these beams was the percentage of longitudinal steel reinforcement (0, 0.707, 1.061, and 1.414%). The main objective of this research is to investigate the possibility of restoring the full load carrying capacity of the reinforced concrete deep beam with and without shear reinforcement by using epoxy resin as the material of repair. All be
... Show MoreBackground: The displacement of artificial teeth during complete denture construction presents major processing errors in the occlusal vertical dimension which were verified at the previous trial denture stage. The aim of this study was to assess the effect of delay in processing after final flask closure and tension application on the vertical acrylic and porcelain teeth displacement of complete dentures constructed from heat cured acrylic and the results were compared with the conventional processing method. Materials and methods: forty samples of identical maxillary complete dentures were constructed from heat polymerized acrylic resin. These samples were subdivided into the following experimental subgroups in which each subgroup contai
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