The primary purpose of the present research was to study the effect of polyvinyl chloride (PVC) powder content on ultrasonic wave velocity in PVC/Epoxy composites. The second part is concerned with the relations of dynamic elastic moduli with the ultrasonic wave velocities, to determine how ultrasonic waves can affect them.
Experimental data have been obtained using the sonic viewer (model -5217 A) device to generate two types of waves, longitudinal waves of frequency 63 kHz and transverse waves of frequency 33 kHz and to measure the transit time required for those waves to travel through individual sample.
The experimental results have shown that the propagation of the ultrasonic velocity increases directly with PVC content in the tested specimens, due to the changes in the dynamical properties that were investigated from the calculated values of the elastic moduli of the composites
Background: In this study we evaluate the effect of plasma treatment (oxygen and argon) gas in two different exposure times on the surface of heat cure and light cure acrylic resin. Materials and method: 100 specimens of heat cure and light cure acrylic resin were fabricated. The measurements of the samples were (75mm, 25mm and 4.5mm) length, width and depth respectively with stopper of 3mm depth. Two types of gas used oxygen and argon in (5,10) min by using (DC-glow discharge plasma device) then we apply cold cure soft lining material, with the help of Instron machine we test the shear stress value. Results: A highly significant effect after argon and oxygen gases treatment in both 5 and 10 min exposure times on shear bond strength to soft
... Show MoreBackground: The PMMA polymer denture base materials are low in thermal and strength properties. The aim of the study was to investigate the change in glass transition temperature, E-Moudulus and coefficient of thermal expansion of acrylic denture base material by addition of Al2O3, TiO2 and SiO2nano-fillers in 5% by weight. Materials and methods: The type of polymerization is free radical bulk polymerization. one hundred twenty (120) specimens were prepared , the specimens were divided into four groups according to the material had been added (one control and three for Al2O3, TiO2 and SiO2nanocomposite) each group was subdivided in to three groups according to the test had been done on it, the degree of transition (Tg) was measured by The d
... Show MoreCurrent research aims to find out:
- Effect of using the active learning in the achievement of third grade intermediate students in mathematics.
- Effect of using of active learning in the tendency towards the study of mathematics for students of third grade intermediate.
In order to achieve the goals of the research, the researcher formulated the following two hypotheses null:
- There is no difference statistically significant at the level of significance (0.05) between two average of degrees to achievement
The glycated haemoglobin A1c(HbA1c) and Fasting blood glucose(FBG) effect on type1 diabetic pateints as a screening tests and as a gold standard for assessing glycemic control in subjects with diabetes were studied . Ninety one blood samples were collected in a peroid between June and the end of November 2012 at AL- Kindy Diabetic Center and Central Child Hospital,48 Females and 43 Males , aging between (11 month- 18 year), are divided into three groups, newly diagnosed , ongoing and healthy control group, with duration of disease between(1 day-3months) and (from birth-8 years) for newly diag
... Show MoreAbstract: Plastic pollution is a major issue of the current century. This waste is found in seas, freshwater, lakes, rivers, coastal areas, and soil. In this article, this article discusses the various sources of plastic pollution, including the manufacturing process of plastics and the addition of materials to improve their properties, as well as the use of single-use plastics that are not recyclable, in addition to burning and illegal waste disposal in the open. The impact on public health is through human exposure to toxins from plastics in the environment directly through inhaling dust and fumes, consuming contaminated food and drink, and skin contact. Indirectly, when marine creatures consume microplastics, they will find their way
... Show MoreObjective: this search aims to test the correlation between job complexity and psychological detachment then stats how the burnout can affect in this relationship and dose the burnout can contribute in development of this relationship. Theoretical framework: the research adopted some questions like how can psychological detachment can make the employee keeping away from work and isolates himself from work environment and how can the job complexity enhance this behavior for employee ,and how can the burnout increase the correlation between job complexity and psychological detachment ?, then trying to extraction some of recommendations may contributes in enhancing practicing and adopting these three variables (job complexity, psych
... Show MoreThe research aims to investigate the possibility of joint auditing in improving the market value of Iraqi companies listed on the Iraq Stock Exchange. The sample was represented by 10 Iraqi companies listed in the Iraq market for the period from 2014-2017 (2 years before implementation and 2 years after implementation) and the research was based on the idea that joint auditing enhances investor confidence and raises their level of security as a result of providing quality and reliable reports, and thus This indicates good news in the market that reflects on the performance of stocks and the market value of companies that adopt joint auditing. The results of the analysis indicate an improvement in the market value, but this improv
... Show MoreIs the subject of the mind took a dimension in philosophy and psychology , and has cared psychologists this topic to a large extent , I started education institutions interest in the capabilities of intelligence since the early twentieth century , and the development of interest in them until he arrived to find Standards and Criteria to identify the degree IQ of any individual , and began to educational institutions interested in mental talent and talented .
The United States is the country chock first of these research projects , but they devoted all their attention on the wish talent mental and Gifted , until I got to the projects, the so-called time ( ( wars of the mind ) ) and projects Schools gifted
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