ABSTRACT Background: Improving the properties of heat- cured and self-cured acrylic resin have been studied by many researchers. However, little studies concerned with visible light cured resin (VLCR) improved through addition of nanofiller are available. The purpose of this study was to evaluate some properties of (VLCR) after addition of SiO2 nanofiller. Materials and Methods: SiO2 nanofiller were added to (VLCR) tray material after being dissolved in tetrahydrofuran (THF) solvent. According to the pilot study 2% SiO2 nanofiller addition exhibited better properties than the other percentages (1%, 3%). The main study conducted involved (100) specimens divided into 5 groups according to the test included. (20) Specimens were selected for each test (10 samples for the control group and 10 samples for the experimental 2% SiO2 nanofiller group). The properties investigated were transverse strength, impact strength, surface hardness, surface roughness, water sorption and solubility. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were used to assess nanofiller distribution and identification of elements. The data were subjected to descriptive statistical analysis and independent sample t-test. Results: The mean value of transverse strength of experimental group increased significantly, while the impact strength of experimental group decreased significantly when compared to control group. A significant increase in surface hardness was noticed in the experimental group, while non-significant increase in surface roughness was observed. The water sorption values were decreased significantly, while a non-significant decrease in water solubility was observed in the experimental group. Conclusion: Addition of SiO2 nanofiller to (VLCR), slightly improve the transverse strength and surface hardness, while water sorption and solubility slightly decreased. The impact strength was significantly deteriorated, while the surface roughness shows non-significant increment.
In this current work, Purpose; to clearly the fundamental idea for constructing a design and
investigation of spur gear made of composite material its comes from the combination of (high
speeds, low noise, oil-les running, light weight, high strength, and more load capability)
encountered in modern engineering applications of the gear drives, when the usual metallic gear
cannot too overwhelming these combinations.
An analyzing of stresses and deformation under static and dynamic loading for spur gear tooth
by finite element method with isoparametric eight-nodded in total of 200 brick element with 340
nods in three degree of freedom per node was selected for this analysis. This is responsible for the
catastropic fa
To achieve sustainability, use waste materials to make concrete to use alternative components and reduce the production of Portland cement. Lime cement was used instead of Portland cement, and 15% of the cement's weight was replaced with silica fume. Also used were eco-friendly fibers (copper fiber) made from recycled electrical. This work examines the impact of utilizing sustainable copper fiber with different aspect ratios (l/d) on some mechanical properties of high-strength green concrete. A high-strength cement mixture with a compressive strength of 65 MPa in line with ACI 211.4R was required to complete the assignment. Copper fibers of 1% by volume of concrete were employed in mixes with four different aspect ratios
... Show MoreFollowing the political development in Iraq Since 7112 exposed kind of political traditions about how to manage the conflicts that have different Iraqi powers .That what was clear since the formation of permanent government since in 7112 .
The case of conflict between political powers in administrating Iraq state and the withdrawal of American Forcesintroduces questions:
0-Is it possible that that the beginning of Iraq state building shall ease this conflict and peacemaking in the post-conflict period?
7- To what extent the Iraqi powerswas to manage their disputes in non-military like elections which was held in 7112?
2- What is the range of the extent of the political operation after the American withdrawal?
The important
The linguistic meaning of the verse in the Arabic dictionaries applies very much to the reality of rent and its effect. This is true of economic growth as a continuous increase in real per capita income in addition to the same thing. Therefore, development does not necessarily achieve a comprehensive and structural increase of the various economic sectors. As the rent came in the sense of a terrible land open Maim any fertilized. And the camel is a ma'aya and a ra'i: that is, it goes in the pasture and returns itself. This is similar to the extraction of oil after it is ready for investment and earn its revenue as soon as it exists or is extracted by external parties. If the rent is first linked to agriculture, especially the fertile lan
... Show MoreThe research in the variables of the political process and government stability tried to show the impact of the political process on political stability first, and then on government stability second, given that the political process that was established in 2005 was aimed at achieving legitimacy, and its most prominent tools are elections, leading to achieving political stability, including government stability. The issue of governmental stability is one of the important issues in Iraq, but it has not been achieved, as a result of several factors, including problems in political action, as the political process has not succeeded in leading Iraq to stability.
This study is concerned with the recent changes that occurred in the last three years (2017-2019) in the marshes region in southern Iraq as a result of the changes in the global climate, the study included all the water bodies in the five governorates that are located in the southern regions of Iraq (Wasit, Maysan, Dhi-Qar, Qadisiyah and Basrah), which represent the marshes lands in Iraq. Scenes of the Landsat 8 satellite are used to create a mosaic to cover the five governorates within a time window with the slightest difference between the date of the scene capture, not to exceed 8 days. The results of calculating the changes in water areas were obtained using the classifier support vector machine, where high accuracy ratios were recorded
... Show MoreAbstract:Leukemia is a cancer of early blood forming cells. Most of them are cancers of white blood cells , however some leukemias start in other blood cell types.Electrolytes have modulatory effects on several biological mechanisms in the body namely as stabilizers,element of structures, essential element for hormonal function and also co-factors for a number of enzymes.In this study serum electrolytes levels were measured in patients with acute leukemia (AL) disorders before and after chemotherapy(anthracycline, doxorubicin, cytarabine ,prednisone, vincristine and doxorubicin) during one month and compared with that of control group. Blood samples were obtained from (43) patients (28 males and 15 females) aged (15-55)years;juset before an
... Show MoreAlthough the events of September 2001 marked the United States' employment of solid forces in its direct comprehensive strategy to counter terrorist organizations and any other challenges to US national security, the United States did not lose sight of the importance of the cultural variable. The cultural variable is the United States' most important instrument of soft power in ensuring its dominance of the international system and promoting its global project. France viewed US soft power as a threat to its own civilizational pattern. Therefore, France considers culture to be an inherent component of its national personality and a cornerstone of its international standing as a major force. Additionally, the US-French political and economic
... Show MoreThis study has been carried out to evaluate the expression level of beta 2 microglobulin gene on patients infected by hepatitis C virus before and after treatment with interferon. The study included 117 hepatitis C patients comprising as 63 pre-treated patients, the range of age was between 20-65 year with a mean age of 48.12 ± 16.1 and 54 post-treated patients with age range was between 23-63 year with the mean of 46.1 ± 18.1. Also it was found that more than half of patients were located within third and fourth decade i.e. 30-49 year, with a percentage of 52.4% and 55.6 % for pre-treatment and post-treatment patients respectively. Moreover , regarding both groups, males are more than females with the ratio of ( 3.2:1) among p
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