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 effect of D phase polyamide (PA6)on the rheological properties, Young Modulus and the thermal expansion coefficient of two blends groups (bitumen-polyamide) were tested. The first group was for bitumen-PA6 blends and the second group for bitumen blended with polymer resulted from the crystallization of PA6-formic acid solution in water(PAFW).The obtained results proved that adding both types of polyamide has led to a rise in toughness and softening point temperature while the penetration Index approached -3 after adding the polyamide. So, all these changes make bitumen-polyamide blends more suitable for use in hot climate regions. The blends properties were explained according to the reaction that takes place between the polyamide and
... Show MoreHydrocarbon production might cause changes in dynamic reservoir properties. Thus the consideration of the mechanical stability of a formation under different conditions of drilling or production is a very important issue, and basic mechanical properties of the formation should be determined. There is considerable evidence, gathered from laboratory measurements in the field of Rock Mechanics, showing a good correlation between intrinsic rock strength and the dynamic elastic constant determined from sonic-velocity and density measurements. The values of the mechanical properties determined from log data, such as the dynamic elastic constants derived from the measurement of the elastic wave velocities in the material, should be more accurate t
... Show MoreHydrocarbon production might cause changes in dynamic reservoir properties. Thus the consideration of the mechanical stability of a formation under different conditions of drilling or production is a very important issue, and basic mechanical properties of the formation should be determined.
There is considerable evidence, gathered from laboratory measurements in the field of Rock Mechanics, showing a good correlation between intrinsic rock strength and the dynamic elastic constant determined from sonic-velocity and density measurements.
The values of the mechanical properties determined from log data, such as the dynamic elastic constants derived from the measurement of the elastic wave velocities in the material, should be more a
This paper presents an analysis of selected qualitative characteristics of pellets produced from rape straw obtained from cultivations subjected to different fertilization treatments and from mixtures of straw selected for testing with crude glycerol obtained as a by-product from biodiesel production. The assessment focused on the following qualities of the obtained pellets: Moisture content, mechanical durability, heating value and main elements, that is, carbon, hydrogen, nitrogen, sulphur, chlorine and oxygen. The obtained results indicated that the different treatment regimens applied in spring rape cultivations had a significant impact on the physicochemical qualities of the straw. In terms of the heating value, traditional fer
... Show MoreNanoparticles are a special group of materials with unique features and extensive applications in diverse fields. The use of nanoparticles of some metals is a viable solution to stop infectious diseases due to the antimicrobial properties of these nanoparticles. The present work demonstrates the effect of silver nanoparticles (AgNPs) on the antibacterial activity of four different antibiotics (amoxicillin, ceftriaxone, chloramphenicol, and penicillin) against eleven Gram-positive and Gram-negative isolates. Disk diffusion method was used to determine the antibacterial activity of various classes of antibiotics in the absence and presence of sub-inhibitory silver nanoparticles of concentration (80 microgram/ml). A synergistic effect was o
... Show MoreEuropean Chemical Bulletin (ISSN 2063-5346) is a peer-reviewed journal that publishes original research papers, short communications, and review articles in all areas of chemistry. European Chemical Bulletin has eight sections, namely
Osteoarthritis (OA) is the most common degenerative joint disorder that ultimately results in the progressive destruction of articular cartilage. The occurrence of knee osteoarthritis (OA) increases with obesity and is more common in women compared with men. Thirty patients (20 females, 10 males) clinically diagnosed with knee OA admitted to Baghdad teaching hospital between January 2015-June 2015. Patients between 35-70 year of age and 30 healthy subject (20 females, 10 males) ages matched. The results showed that increased body mass index (BMI) is a well-recognized risk factor for knee osteoarthritis, and the effect of obesity is a stronger predictor of developing knee OA symptoms in women than men. There was also a significant diffe
... Show MoreA total of 150 deep eutectic solvents (DESs) with varying salt, hydrogen bond donor, and molar ratios were studied to develop a screening tool for separating toluene-heptane mixtures. The activity coefficient at infinite dilution (γ∞) of each DES was predicted using COSMO-RS, and selectivity (S∞), capacity (C∞), and performance index (PI) were calculated. Key DES properties, including density, viscosity, melting/freezing point, surface tension, and conductivity, were compiled from the literature to create a DES property library. A comprehensive screening tool with four evaluation criteria was developed, which identified ethyl triphenylphosphonium bromide:ZnCl2 (1:4) as the optimal solvent for toluene-heptane separation. Tetrabutyl- b
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