Background: Rehabilitation of the carious tooth to establish tooth structure integrity required cavity design that show a benign stress distribution. The aim of this study was to investigate the influence of the cavity position on the stress values in the reamining tooth structure restored with amalgam or resin composite. Materials and methods: Seven 2-D models of maxillary first premolar include class I cavity design was prepared, one sound tooth (A) 3 composite (B1, B2, and B3) and 3 amalgam (C1, C2, and C3). In design (BI and C1) the cavity position is in the mid distance between bacc-lingual cusp tip, design (B2 and C2) and (B3 and C3) shifted toward the buccal cusp and the lingual cusp for 0.5 mm respectively. One hundred N vertical load was applied and stress analysis was applied using Ansys v14 software. Results: The maximum Von Mises stress 585.35 MPa in the sound tooth and (899,46, 690.46, and 941.47) in central, buccal, and lingual cavities position filled with a composite restoration respectively. Whereas, the highest stress (1540.37 MPa), (1233.09 MPa) and (1214.34 MPa) appears with a central, buccal and lingual cavities filled with amalgam respectively. Conclusion: Reestablishment of the stress level of maxillary premolars subjected to class I cavity preparations are cavity bacc-lingual position and restorative-system-dependent. Key words: Cavity position, class I, amalgam, composite, stress level.
Research deals the crises of the global recession of the facets of different and calls for the need to think out of the ordinary theory and find the arguments of the theory to accommodate the evolution of life, globalization and technological change and the standard of living of individuals and the size of the disparity in income distribution is not on the national level, but also at the global level as well, without paying attention to the potential resistance for thought the usual classical, Where the greater the returns of factors of production, the consumption will increase, and that the marginal propensity to consume may rise and the rise at rates greater with slices of low-income (the mouths of the poor) wi
... Show MoreThe biological effects of pulsed N2-laser on the old world screw-worm fly, Chrysomya bezziana Villeneuve in the pupal stage were investigated. Different laser parameters were involved in this work. The old pupae of 1, 2, 3, 4 and 5 days were exposed to laser radiation during 10, 30 and 60 second with repetition rate 10, 20 and 30 pulse/second. The percent of normal adults emergence (female and male) was investigated. The results showed that the adults emergence was highly decreased as the repetition rate and exposure time increased when the pupae irradiated for 1, 2 and 3 days old as compared with 4 and 5 days. The results also indicated that the pupal period was significantly increased of irradiated pupae for 1, 2, 3 and 4 days old, whi
... Show MoreAging of asphalt pavements typically occurs through oxidation of the asphalt and evaporation of the lighter maltenes from the binder. The main objective of this study is to evaluate influence of aging on performance of asphalt paving materials.nAsphalt concrete mixtures, were prepared, and subjected to short term aging (STA) procedure which involved heating the loose mixtures in an oven for two aging period of (4 and 8) hours at a temperature of 135 o C. Then it was subject to Long term aging (LTA) procedure using (2 and 5) days aging periods at 85 o C for Marshall compacted specimens. The effect of aging periods on properties of asphalt concrete at optimum asphalt content such as Marshall Properties, indirect tensile strength at 25 o C,
... Show MoreThe adopted accelerated curing methods in the experimental work are 55ºC and 82ºC according to British standard methods. The concrete mix with the characteristics compressive strength of 35MPa is design according to the ACI 211.1, the mix proportion is (1:2.65:3.82) for cement, fine and coarse aggregate, respectively. The concrete reinforced with different volume fraction (0.25, 0.5 and 0.75)% of glass, carbon and polypropylene fibers. The experimental results showed that the accelerated curing method using 82ºC gives a compressive strength higher than 55ºC method for all concrete mixes. In addition, the fiber reinforced concrete with 0.75% gives the maximum compressive strength, flexural and splitting tensile strength for all types of
... Show More- baumannii is an aerobic gram negative coccobacilli, it is considered multidrug resistance pathogen (MDR) and causes several infections that are difficult to treat. This study is aims to employ physical methods in sterilization and inactivation of A. baumannii, as an alternative way to reduce the using of drugs and antibiotics.
Cold Atmospheric Plasma was generated by one electrode at 20KV, 4 power supply and distance between electrode and sample was fixed on 1mm. A. baumannii (ATCC 19704 and HHR1) were exposed to Dielectric Barrier Discharge type of Cold Atmospheric Plasma (DBD-CAP) for several periods
Z-scan has been utilized for studying the non-linear properties and optical limiting behaviors of the dye Copper Phthalocyanine thin films. The refractive index is negative, which indicates a self-defocusing behavior and non-linear absorption coefficient (
Objective: Evaluation of the poly ether keton keton polymer (PEKK) coating material on the commercial pure titanium disks (CP Ti) with or without laser surface structuring. Design: In vitro experimental study of PEKK polymer coated material on the CP Ti disks with or without laser surface structuring. Materials and methods: coating the surface of the commercial pure titanium (CP Ti) disks with PEKK polymer was performed via using frictional mode CO2 laser, then the samples disks analyzed by using FESEM. Results: the FESEM reveal good adherence and distribution of the PEKK coated material over the CP Ti substrate by using the frictional mode CO2 laser at 2 watt and 6 ms pulse duration. Conclusion: the frictional mode CO2 laser considered an
... Show MoreThe experiment was conducted in the old botanical garden belong to Biology Department/ College of Education for Pure Science - Ibn Al-Haitham/Baghdad University for growing season 2015-2016 to study the effect of irrigation with four concentrations of sodium chloride (0, 50, 100, 150) mM.L-1 and spraying with selenium in three concentrations (0, 10, 20) mgL-1 on growth of broad bean plant using clay pots. The experiment was design according to completely randomized design (CRD) with three replications. Results indicated that broad bean plant irrigated with saline water and increasing concentrations of sodium chloride in growth medium caused a significant decreased in the plant growth parameters (plant height, no. of compound leaves. Plant-1
... Show MoreThis paper presents L1-adaptive controller for controlling uncertain parameters and time-varying unknown parameters to control the position of a DC servomotor. For the purpose of comparison, the effectiveness of L1-adaptive controller for position control of studied servomotor has been examined and compared with another adaptive controller; Model Reference Adaptive Controller (MRAC). Robustness of both L1-adaptive controller and model reference adaptive controller to different input reference signals and different structures of uncertainty were studied. Three different types of input signals are taken into account; ramp, step and sinusoidal. The L1-adaptive controller ensured uniformly bounded
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