Background: to evaluate the effect of different dentifrices on the surface roughness of two composite resins (nanofilled-based and nanoceramic – based composite resins). Materials and methods: Forty specimens (diameter 12 mm and height of 2mm) prepared from different composite resin materials: Z350 (nanofilled composite, and Ceram-X (nanoceramic) .they were subjected to brushing simulation equivalent to the period of 1 year. The groups assessed were a control group brushed with distilled water (G1), Opalescence whitening toothpasteR (G2), Colgate sensitive pro-relief (G3) and Biomed Charcoal Toothpaste (G4). The initial and final roughness of each group was tested by surface roughness tester. The results were statistically analyzed using ANOVA and Tueky test at 0.05 significance level. Results: the surface roughness of the two tested composites brushed with the tested dentifrices was statistically higher than the roughness found in control group. Comparison among the three types of dentifrices showed that there was a statistically high significant difference in the surface roughness among all subgroups. Charcoal Toothpaste showed the highest surface roughness increase. Conclusion: Whitening dentifrices increase the surface roughness of dental composite thereby compromising its durability. Changes in composite depended on the material itself and the dentifrices used.
In this research a theoretical study has been carried out on the behavior and strength of simply supported composite beams strengthened by steel cover plate taking into consideration partial interaction of shear connectors and nonlinear behavior of the materials and shear connectors. Following the procedure that already has been adopted by Johnson (1975), the basic differential equations of equilibrium and compatibility were reduced to single differential equation in terms of interface slip between concrete slab and steel beam. Furthermore, in order to consider the nonlinear behavior of steel, concrete and shear connectors, the basic equation was rearranged so that all terms related to materials are isol
... Show MoreIt is suitable to use precast steel-concrete composite beams to quickly assemble a bridge or a building, particularly in isolated regions where cast-in-situ concrete is not a practical option. If steel-concrete composite beams are designed to allow demountability, they can also be extremely useful in the aftermath of natural disasters, such as earthquakes or flooding, to replace damaged infrastructure. Furthermore, rapid replacement of slabs is extremely beneficial in case of severe deterioration due to long-term stressors such as fatigue or corrosion. The only way to rapidly assemble and disassemble a steel-concrete composite structure is to use demountable shear connectors to connect/disconnect the steel beams to/from the concrete slab. I
... Show MoreThis study has been carried out in the Station of Poultry Researches which is affiliated to the General Office of Agricultural Researches / Ministry of Agriculture during the period from 25/02/2019 to 08/04/2019 (42)days .Five hundred unsexed one day old chick of type (Ross 308) used in this study, and has been fed on diets which oleuropeinin has been added to it with the levels 2,2.5,3 and3.5 g/kg as a feed for the treatments T2 , T3 , T4 and T5 respectively and compared to the control treatment T1 which is devoid of addition, every treatment included Four replicates each one has 25 birds in order to study the effect of adding a various levels of oleuropein into the diet on the production and physiological performance for broilers. The res
... Show MoreThis study was conducted in the poultry field of the College of Agricultural Engineering Sciences / University of Baghdad for the period from 10/15/2021 to 11/25/2021 in order to show the effect of adding different levels of Ganoderma lucidum to broiler diets on microbial and immunological In it, 200 unsexed (Ross 308) chicks of one day old breed were used, with a starting weight of (40) g. The chicks were distributed and randomly divided into four treatments with 50 birds for each treatment. One treatment included five replicates (10 birds/repeat) and the experiment treatments were T1, T2, and T3, T4 and the percentages of adding reishi mushrooms 0, 0.5, 1, 1.5 g/kg of feed respectively, and the birds were fed for the duration of the exper
... Show MoreSolar energy usage in Iraq is facing many issues; one of those is the accumulation “of the dust on the surface of the solar module which” would highly lower its efficiency. The present work study the effect of dust accumulation” on installing fixed solar modules with different inclined angles 15o, 33o, 45o, 60o. Evaluation of the solar modules performance under different circumstance conditions such as rain, wind and humidity are considered in study of dust effect on solar module performance. The results show that the lowest output average efficiencies of solar modules occurs at 15o horizontally inclined angle are 7.4% , 6.7% , 8.0% , 8.1%, and 8.4% for the cor
... Show MoreThe present expermint was designed to determine the effect of Sodium Selenite (0.5 mg/kg) and Vitamin A (10 mg/kg) in FSH and LH level in Albino Male Mice treated with Hexavalent Chromium (1000 ppm). `This study included 48 mice divided into six groups (1st group treated with distilled water and the 2nd group treated with Sesame Oil were considered as control group, 3th group exposed to Hexavalent chromium , 4th group treated with Sodium Selenite and exposed to Hexavalent Chromium , 5th group treated with Vitamin A and exposed to Hexavalent Chromium and 6th group treated with Sodium Selenite and Vitamin A and exposed to Hexavalent Chromium ) . The treatment lasted for 35 days. The results showed a significant (P ? 0.05) decrease in FSH an
... Show MoreTrickle irrigation is one of the most conservative irrigation techniques since it implies supplying water directly on the soil through emitters. Emitters dissipate energy of water at the end of the trickle irrigation system and provide water at emission points. The area wetted by an emitter depends upon the discharge of emitter, soil texture, initial soil water content, and soil permeability. The objectives of this research were to predict water distribution profiles through different soils for different conditions and quantify the distribution profiles in terms of main characteristics of soil and emitter. The wetting patterns were simulated at the end of each hour for a total time of application of 12 hrs, emitter disch
... Show MoreA free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of
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