An acidic environment causes surface changes of resin composites. Filler particlesize and filler distribution also have a direct effect on these surface changes. This invitro study evaluated the influence of Pepsi Cola drink on the surface roughness ofComposan LCM and Composan Ceram over time. Sixteen disc shaped specimens(10mm diameter, 2mm thickness) of each resin composite were fabricated, therebyforming two groups (n= 8). Surface roughness (Ra) was analyzed after 24 hrs beforeexposure to beverage. The specimens were submitted to a five minutes immersion inPepsi Cola three times daily interrupted by immersion in deionized distilled water (37C˚). Surface roughness measurements were done at 10, 30, and 60 days intervals. Datawere submitted to paired t-test. There was a statistically highly significant (p <0.001)increase in surface roughness values of the tested composites after 30 days and 60days immersion in Cola drink. Composan LCM exhibited a significantly (p <0.05)higher surface roughness values than Composan Ceram.The surface roughness of the composite materials are significantly affected byexposure to acidic drink over time, highly filled micro hybrid composites with smallfiller particle size are significantly more resistant to acid erosion.
The study investigates the water quality of the Orontes River, which is considered one of the important water recourses in Syria, as it is used for drinking, irrigation, swimming and industrial needs. A database of 660 measurements for 13 parameters concentrations used, were taken from 11 monitoring points distributed along the Orontes River for a period of five years from 2015-2019, and to study the correlation between parameters and their impact on water quality, statistical analysis was applied using (SPSS) program. Cluster analysis was applied in order to classify the pollution areas along the river, and two groups were given: (low pollution - high pollution), where the areas were classified according to the sources of pollution to w
... Show MoreIn this study, two active galaxies (NGC4725, NGC4639) have been chosen to study their morphological and photometric properties, by using the IRAF ISOPHOTE ELLIPS task with griz-filters. Observations are obtained from the Sloan Digital Sky Survey (SDSS) which reaches now to the DATA Release (DR14). The data reduction of all images (bias and flat field) has been done by SDSS Pipeline. The surface photometric investigation was performed like the magnitude. Together with isophotal contour maps, surface brightness profiles and a bulge/disk decomposition of the images of the galaxies, although the disk position angle, ellipticity, and inclination of the galaxies have been done. Also, the color of galaxies was studied, where chromatic distribution
... Show MoreIn this research, we studied the effect of concentration carriers on the efficiency of the N749-TiO2 heterogeneous solar cell based on quantum electron transfer theory using a donor-acceptor scenario. The photoelectric properties of the N749-TiO2 interfaces in dye sensitized solar cells DSSCs are calculated using the J-V curves. For the (CH3)3COH solvent, the N749-TiO2 heterogeneous solar cell shows that the concentration carrier together with the strength coupling are the main factors affecting the current density, fill factor and efficiency. The current density and current increase as the concentration increases and the
A theoretical calculation of the reorganization energies is demonstrated for semiconductor (TiOâ‚‚, ZnO) and organic dye (safranine T, and coumarin) with a variety solvent such that (water, 1Âpropanol, Formamide, Acetonitrile and Ethanol). The reorganization energy values for dye –semiconductor interface system are large in high polar solvent (water 741 .0 ï¬ , Acetonitrile 708 .0 ï¬ , Ethanol 669 .0 ï¬ ) and small in low polar solvent(1Âpropanol 635 .0 ï¬ . The reorganization energy in safranine T –semiconductor system is larger ( 635 741.0 ï€ )than in coumarin –semiconductor for with the same solvents ( 612
... Show MoreThis study included the fabrication of compound (Tl2-xHgxBa2-ySryCa2Cu3O10+δ) in a manner solid state and under hydrostatic pressure ( 8 ton/cm2) and temperature annealing(850°C), and determine the effect of the laser on the structural and electrical properties elements in the compound, and various concentrations of x where (x= 0.1,0.2,0.3 ). Observed by testing the XRD The best ratio of compensation for x is 0.2 as the value of a = b = 5.3899 (A °), c = 36.21 (A °) show that the installation of four-wheel-based type and that the best temperature shift is TC= 142 K .When you shine a CO2 laser o
... Show MoreThe performance of a diesel engine was tested with diesel oil contaminated with glycol at the engineering workshop/Department of Agricultural Machines and Equipment / College of the Agricultural Engineering Sciences at the University of Baghdad. To investigate the impact of different concentrations of glycol on the performance of a diesel engine, an experimental water-cooled four-stroke motor was utilized, with oil containing 0, 100, and 200 parts per million (ppm). Specific fuel consumption, thermal efficiency, friction power, and exhaust gas temperature were examined as performance indicators. To compare the significance of the treatments, the study employed a full randomization design (CRD), with three replicates for each treatment at th
... Show MoreThe performance of a diesel engine was tested with diesel oil contaminated with glycol at the engineering workshop/Department of Agricultural Machines and Equipment / College of the Agricultural Engineering Sciences at the University of Baghdad. To investigate the impact of different concentrations of glycol on the performance of a diesel engine, an experimental water-cooled four-stroke motor was utilized, with oil containing 0, 100, and 200 parts per million (ppm). Specific fuel consumption, thermal efficiency, friction power, and exhaust gas temperature were examined as performance indicators. To compare the significance of the treatments, the study employed a full randomization des
The performance of a diesel engine was tested with diesel oil contaminated with glycol at the engineering workshop/Department of Agricultural Machines and Equipment / College of the Agricultural Engineering Sciences at the University of Baghdad. To investigate the impact of different concentrations of glycol on the performance of a diesel engine, an experimental water-cooled four-stroke motor was utilized, with oil containing 0, 100, and 200 parts per million (ppm). Specific fuel consumption, thermal efficiency, friction power, and exhaust gas temperature were examined as performance indicators. To compare the significance of the treatments, the study employed a full randomization des
This research aims to discuss an important issue because of its role in increasing the efficiency of financial markets and boost investor confidence by a insider trading, which arises as a result of leaking secret information to some investors and reliable in the process of trading shares in the Iraq Stock Exchange And thus obtain abnormal profits at the expense of other investors. Research was based on the assumption that " Where shortcomings in local regulations relating to disclosure and insider trading in accounting information leads to the activate the phenomenon of insider trading in accounting information in the Iraq Stock Exchange and including a negative impact on investors' decisions ". and Because of the difficulty the discove
... Show MoreBackground: Polymethyl methacrylate (PMMA) is the most commonly used material in denture fabrication. The material is far from ideal in fulfilling the mechanical requirements, like low impact and transverse strength, poor thermal conductivity. The purpose of this study was to evaluate the effect of addition a composite of surface treated Nano Aluminum oxide (Al2O3) filler and plasma treated polypropylene fiber (PP) on some properties of denture base material. Materials and methods: One hundred fifty prepared specimens were divided into 5 groups according to the tests, each group consisted of 30 specimens and these were subdivided into 3 groups (unreinforced heat cured acrylic resin as control group),reinforced acrylic resin with( 0.5%wt Nan
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