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Effects of Artificial Aging on Some Properties of Room-Temperature-Vulcanized Maxillofacial Silicone Elastomer Modified by Yttrium Oxide Nanoparticles

Abstract Background: The daily usage of maxillofacial prostheses causes them to mechanically deteriorate with time. This study was aimed to evaluate the reinforcement of VST50F maxillofacial silicone by using yttrium oxide (Y2O3) nanoparticles (NPs) to resist aging and mechanical deterioration. Materials and Method: Y2O3 NPs (30–45nm) were loaded into VST50F maxillofacial silicone in two weight percentages (1 and 1.5 wt%), which were predetermined in a pilot study as the best rates for improving tear strength with minimum increase in hardness values. A total of 120 specimens were prepared and divided into the control and experimental groups (with 1 and 1.5 wt% Y2O3 addition). Each group included 40 specimens, 10 specimens for each parameter tested (i.e., tear strength, surface roughness, hardness, tensile strength and elongation percentage). Specimens were artificially aged in a weathering chamber for 150 h and then tested. Data were analyzed by ANOVA and Tukey’s honestly significant difference (HSD). Statistical significance was set to P ≤ 0.05. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were also conducted. Results and Discussion: SEM results showed that Y2O3 NPs were distributed well within the silicon matrix. FTIR results indicated that the NPs were physically dispersed within VST50F silicone without chemical interaction. After 150 h of accelerated artificial aging, adding Y2O3 NPs significantly increased the tear strength, hardness, surface roughness, and elongation percentage. Tensile strength increased non significantly. Conclusion: Adding Y2O3 NPs as fillers improved the mechanical properties of artificially aged maxillofacial silicone elastomer. Keywords: maxillofacial silicone, Y2O3, nanoparticles, fillers, artificial aging.

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Publication Date
Wed Nov 24 2021
Journal Name
Iraqi Journal Of Science
Classification of soil infiltration rate depending on the Hydrological soil group map South East Iraq

The study area is located in the East of Missan governorate, southeast of Iraq between (32°'29.52" – 32°37'30") latitude and (46°46'21.16" – 47°58'53.52")longitude. It encompasses an area of (1858 ) with elevation ranges from 8 to 165m. Soil is a natural body that exists as part of the pedosphere and which performs four important functions. It is a medium for plant growth and a means of water storage, supply and purification. The spatial mapping of soil usually involves delineating soil types that have identifiable characteristics. The delineation is based on many factors such as geomorphologic origin and conditions under which the soil is formed. Hydrologic soil group (HSG) refers to the classification of soils based on their ru

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Publication Date
Wed Jul 29 2020
Journal Name
Iraqi Journal Of Science
Comparison Between Confined and Unconfined Laser Peening Effect on the Fatigue Life of Composite Materials

Mechanical Engineering Department/ University of Technology- Baghdad.

Confinement layer is considered as the most important parameter during the laser shock peening (LSP) treatment.  In this paper, its effect on the surface treatment effectivity of composite materials was investigated. The composite used in this research was fabricated using hand lay-up as a manufacturing process. The matrix material was built from unsaturated polyester resin and reinforced with 2.5% volume fraction of micro particles of aluminum powder. Fatigue test was conducted at room temperature with constant amplitude stress and a stress ratio of R =-1, before and after LSP treatment. LSP was applied with and without confinement layer at the same level

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Publication Date
Sat Sep 30 2017
Journal Name
Al-khwarizmi Engineering Journal
Study the Effect of Multilayer Single Point Incremental Forming on Residual Stresses for Bottom Plates

Abstract

 

Knowing the amount of residual stresses and find technological solutions to minimize and control them during the production operation are an important task because great levels of deformation which occurs in single point incremental forming (SPIF), this induce highly non-uniform residual stresses. In this papera propose of a method for multilayer single point incremental forming with change in thickness of the top plate (0.5, 0.7, 0.9) mm and lubrication or material between two plates(polymer, grease, grease with graphite, mos2) to knowing an effect of this method  and parameters on residual stresses for the bottom plates. Also compare these results for the

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Publication Date
Sun Dec 01 2002
Journal Name
Iraqi Journal Of Physics
The Role of Plasm Lipid Profile on RBC Aggregation and Sedimentation Changes in Diabetic Patients

The aggregation capacity of human reb blood cells lies between that of the non- aggregated arythrocyte and the remarkably full sedimentation. As the ability to aggregate is atributed to many factors such as the availability of macromolecules and plasma lipids, the role of plasm lipid profile on RBC aggregation and sedimentation changes in normal and diabetic patients is studied.Also serum lipid profile measurement (Total cholesterol, Triglyceride, HDL, LDL, VLDL) in normal and diabetic subjects were made. The principle of measurement includes detecting the transmitted laser light through a suspension of 10% diluted red blood cells in plasma. In all diabetics, the raulux formation and sedimentation rate is enhanced.

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Publication Date
Sun Oct 02 2011
Journal Name
Journal Of The Faculty Of Medicine Baghdad
The impact of inflammation on Resistin, Insulin and Troponin I in Acute Myocardial Infarction patients

Background: Myocardial Infarction (MI) is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque. It has been suggested that the adipose tissue may play an important role in mediating this chronic inflammatory process. Inflammatory responses are involved in the initiation and progression of atherosclerotic plaques. Resistin is a cysteine-rich polypeptide that is expressed at relatively lower levels in human adipocytes but higher levels in macrophages. Insulin is an important hormone as it regulates the level of glucose, in the blood. This protein is formed in specialized cells of the pancreas called beta islet cells.
Subjects and Methods:The study included 50 patient

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
((The Mediator Role of Self Management on the RelationShip Between Work Stresses and Organizational Alienation))

   The study aims to test the relationship of work pressure to its dimensions (role conflict, ambiguity of role, workload and nature of work) as an independent variable and its effect on organizational alienation by its dimensions (disability, lack of power, indifference, animosity, social isolation and self-alienation) (Restraint and confidence in negation, initiative, adaptation and living conscience) as a mediator variable, in some faculties of Baghdad University of Science (Medicine and Engineering) and Humanity (Education and Literature). The data was collected on the practical side, which was applied randomly (306) of the teachers and teachers of the colleges (56) items, which included the main research variables

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Publication Date
Wed May 25 2022
Journal Name
Iraqi Journal Of Science
Using Persistence Barcode to Show the Impact of Data Complexity on the Neural Network Architecture

    It is so much noticeable that initialization of architectural parameters has a great impact on whole learnability stream so that knowing  mathematical properties of dataset results in providing neural network architecture a better expressivity and capacity. In this paper, five random samples of the Volve field dataset were taken. Then a training set was specified and the persistent homology of the dataset was calculated to show impact of data complexity on selection of multilayer perceptron regressor (MLPR) architecture. By using the proposed method that provides a well-rounded strategy to compute data complexity. Our method is a compound algorithm composed of the t-SNE method, alpha-complexity algorithm, and a persistence barcod

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Publication Date
Wed May 10 2023
Journal Name
Journal Of Engineering
Effect of the Iranian Seperation Dikes on the Water Salinity Patterns Within Al Huweizah Marsh

Al Huweizah Marsh is considered as the largest marsh at the southern part of Iraq. About one third of the marsh is located within the Iranian territory. Iran began to construct earth dikes along the Iraqi-Iranian international borders to separate the Iranian part of the marsh. The electrical conductivity, EC, value was adopted to be the indicator for the water salinity within the marsh. A steady two-dimensional water quality routing model was implemented by using the RMA2 and RMA4 softwares within the SMS computer package to estimate the distribution of the
EC values within the marsh seasonally during the wet, moderate and dry water years. The EC distribution Patterns were estimated considering the expected two cases of the marsh futu

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Particle size effect on XRF measurements of Copper and Zinc particles suspended in hydrocarbon materials

Copper and Zinc powders with different particle sizes were subjected to sieving of range (20-100?m) and He-Ne laser system to determine the particle size . 1wt% from each powders was blended carefully with 99wt% from Iraqi oil . Microscopic examination were carried for all samples to reveal the particle size distribution . XRF intensity measurements were conducted for all suspended samples , and the relation between XRF intensity and the particle size was found .

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Publication Date
Tue Mar 14 2023
Journal Name
Iraqi Journal Of Science
On the Dynamics of Prey-Predator Model Involving Treatment and Infections Disease in Prey Population

In this paper, a mathematical model consisting of the prey- predator model with treatment and disease infection in prey population is proposed and analyzed. The existence, uniqueness and boundedness of the solution are discussed. The stability analyses of all possible equilibrium points are studied. Numerical simulation is carried out to investigate the global dynamical behavior of the system.

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