In this research the effect of cooling rate and mold type on mechanical properties of the eutectic
and hypoeutectic (Al-Si) alloys has been studied. The alloys used in this research work were (Al- 12.6%Si
alloy) and (Al- 7%Si alloy).The two alloys have been melted and poured in two types of molds with
different cooling rates. One of them was a sand mold and the other was metal mold. Mechanical tests
(hardness, tensile test and impact test) were carried out on the specimens. Also the metallographic
examination was performed.
It has been found that the values of hardness for the alloys(Al-12.6%Si and Al-7%Si) which poured in
metal mold is greater than the values of hardness for the same alloy when it poured in a heated metal
mold at different temperatures or in sand mold. The strength and impact resistance for the alloys (Al-
12.6%Si and Al-7%Si) are greater when these were poured in a metal molds than that when it poured in a
sand mold.
Furthermore, the higher cooling rates enhance the strength, hardness and impact resistance for the
two alloys, while the low cooling rates reduces these mechanical properties.
The percentage of elongation and the amounts of formed porosity decreased when the cooling rates
increased
The research aims at identifying the organizational performance of the kindergarten teachers and defines the educational environment of kindergarten children. To achieve the objectives of the research, the researcher adopted the organizational performance scale for (Saadi, 2016), which was applied to kindergarten teachers. The scale consists of (43) paragraphs, and has good reliability and validity, as the coefficient of reliability (84.0) in a retest method, and (87.0) using the formula Alpha Kronbach. Additionally, the researcher adopted the educational environment scale for (Radam, 2015); the scale consists of (66) paragraphs, and it enjoys a good reliability and validity, as the coefficient of reliability (89.0) method of reliability
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This present work adopts the analytic and descriptive methodology to recognize and analyze the major challenges faced by the Iraqi government. The study focuses on the press and national partiers’ cabipility of changing and unifying the opinions of the public in a way that serves the Iraqi interest, taking into account the fact that the press is the fourth authority after the three major authorities, (Executive, Legislation and Judicial). The researcher has concluded that the Iraqi press and parties initiated a national front with the Iraqi people against the government’s signature of the treaty of (1930). The national front illustrated that signing the treaty strengthens the authority of the British occupation u
... Show MoreThe aim of this study is to investigate the effect of environmental management accounting information (EMAI) on the design process of environmental and sustainable products of Iraqi industrial companies. This process has five different sub-processes: research process, analysis process, conceptual design process, detailed design process and design production process. The study uses the quantitative approach as the questionnaire was designed and distributed to 87 quality managers, production managers, design managers and financial managers. The MANOVA analysis shows that EMAI has a positive and significant effect on three of these processes, namely research process, analysis process and detailed design process, while EMAI has an insi
... Show MoreThe irony pushes us to inquire about what is in the text of contradiction, irony, suspense, and other acts of paradox, as well as a departure from what is logical, or familiar, that attracts the attention of the addressee, and this is what drives us to introspect the text and interrogate it in order to get to know the intended product of the text or its real or metaphorical intent. On the other hand, the irony is more in the literary text than in the scientific texts. Therefore, critics add the word literature to it in their definition.
As it is represented by the paradox, we will seek to study the paradox of the title and the problematic that it may pose as the beginning of the text, and i
... Show MoreThe nuclear structure included the matter, proton and neutron densities of the ground state, the nuclear root-mean-square (rms) radii and elastic form factors of one neutron 23O and 24F halo nuclei have been studied by the two body model of within the harmonic oscillator (HO) and Woods-Saxon (WS) radial wave functions. The calculated results show that the two body model within the HO and WS radial wave functions succeed in reproducing neutron halo in these exotic nuclei. Moreover, the Glauber model at high energy has been used to calculated the rms radii and reaction cross section of these nuclei.
Road-side dust samples were collected during August in 2020 from selected areas of, Al-Rusafa, Baghdad, Iraq. A sedimentological and mineralogical analysis of street dust was conducted. Three areas were selected to study street dusts which are Al-Baladitat, Al-Obaidi and Ziona. The laboratory analyses were done in the Department of Geology, College of Science, University of Baghdad. The heavy metal contents were determined in the roadside dust using XRF Method. It was found that the dust is of muddy texture, and is believed to be transmitted with the various storms blowing on Baghdad or by the wheels of Cars. The results of mineralogical investigation revealed that the dust samples composed of quartz, feldspar, calcite, gypsum and s
... Show Moreالخلفية: التهاب المفاصل الرَثَيَانِي أو الداء الرثياني أو الالتهاب المفصلي الروماتويدي هو مرض مزمن، من الأمراض الانضدادية التي تؤدي بالجهاز المناعي لمهاجمة المفاصل، مسببة التهابات وتدميرًا لها. ومن الممكن أيضًا أن يدمر جهاز المناعة أعضاء أخرى في الجسم مثل الرئتين والجلد. وفي بعض الحالات، يسبب المرض الإعاقة، مؤدية إلى فقدان القدرة على الحركة والإنتاجية. ويتم تشخيص المرض بواسطة تحاليل دم مخبرية مثل تحلي
... Show MoreBackground: Frovatriptan succinate (FVT) is an effective medication used to treat migraines; however, available oral formulations suffer from low permeability; accordingly, several formulations of FVT were prepared. Objective: Prepare, optimize, and evaluate FVT-BE formulation to develop enhanced intranasal binary nano-ethosome gel. Methods: Binary ethosomes were prepared using different concentrations of phospholipid PLH90, ethanol, propylene glycol, and cholesterol by thin film hydration and characterized by particle size, zeta potential, and entrapment efficiency. Furthermore, in-vitro, in-vivo, ex-vivo, pharmacokinetics, and histopathological studies were done. Results: Regarding FVT-loaded BE, formula (F9) demonstrated the best paramet
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