In this work, functionally graded materials were synthesized by centrifugal technique at different
volume fractions 0.5, 1, 1.5, and 2% Vf with a rotation speed of 1200 rpm and a constant rotation time, T
= 6 min . The mechanical properties were characterized to study the graded and non-graded nanocomposites
and the pure epoxy material. The mechanical tests showed that graded and non-graded added alumina
(Al2O3) nanoparticles enhanced the effect more than pure epoxy. The maximum difference in impact strength
occurred at (FGM), which was loaded from the rich side of the nano-alumina where the maximum value was
at 1% Vf by 133.33% of the sample epoxy side. The flexural strength and Young modulus of the functionally
graded samples were enhanced by 43.69% and 52.74%, respectively, if loaded from the alumina-rich side.
On the other hand, when loading (FGM) from the epoxy side, the amount of decrease in bending resistance
was 122.4% while the improvement in bending modulus was 81.11% compared to pure epoxy. Scanning
electron microscopy (SEM) revealed the fracture surface of the impact samples and the gradient scattering of
nanoparticles in the epoxy matrix. Numerous applications can be used to manufacture the functionally
graded material by centrifugal casting method, including for the manufacture of gears and all bending
applications such as leaf springs.
ت نايبتسلاا ثحابلا مدختسا دقو ,ةيداصتقلاا تادحولا ةميق ىلع انوروك ةحئاج لظ يف يلخادلا قيقدتلا ريثأت ةيداصتقلاا تادحولا فادها قيقحت يف مهسي يلخادلا قيقدتلا نا ثحبلا تاجاتنتسا مها تناكو , ثحبلا تاريغتم نيب ةقلاعلا نايبل رطاخملا ةرادأو اهتءافكو اهتيلعاف نيسحتو قيقدتلا عقوم زيزعت ىلع لمعلا تايصوتلا مها تناكو امك, ةمكوحلا تايلمعو ةباقرلاو قيقحتل رارمتسأب ئراوطلا ططخ ثيدحتو ةبقارمو ةحضاو تازفحم ءاشناو ةلمتحم
... Show MoreThe principal components analysis is used in analyzing many economic and social phenomena; and one of them is related to a large group in our society who are the university instructors. This phenomenon is the delay occurred in getting university instructor to his next scientific title. And as the determination of the principal components number inside the principal components depends on using many methods, we have compared between three of these methods that are: (BARTLETT, SCREE DIAGRAM, JOLLIFFE).
We concluded that JOLLIFFE method was the best one in analyzing the studying phenomenon data among these three methods, we found the most distinguishing factors effecting on t
... Show MoreIt is very well known in the planning publications that when creating spacing development to a region or sub-region, it can be able to make more than an alternative consisting with the strategic directions overtaken from the actual development of region and the situational and developmental objectives needed. However, the difficulty facing the situational planning is in selecting one of these alternatives to be the best in order to make a balanced situational re-structure, and achieving the economic, social and civil objectives. The developmental situation elements in the regions and governorates, including (Karbala) impose themselves as situational power which implies the process of re-structural arrangement where the situational develo
... Show Moreالملخص: لتحقيق أهداف البحث قامت الباحثتان ببناء مقياس للتفكك الاسري اعتمادا على نظرية (باندورا) وتكون بصورته النهائية من (24) فقرة ، وطبق المقياس على عينة البحث البالغة (150) تلميذ وتلميذة تم اختيارهم بالطريقة العشوائية البسيطة من مجتمع البحث ،وبعد جمع البيانات تم معالجتها باستعمال الوسائل الإحصائية منها الاختبار التائي، وتحليل التباين الرباعي والاختبار الفائي، وتوصل البحث الى النتائج الأتية :ان أفراد عينة ال
... Show MoreThe environmental problems that have emerged recently as a result of pressure on the environment due to the increase in population size, especially in urban cities, where this increase was accompanied by the need for housing as well as the need for services and activities. This led to the establishment of many vertical residential buildings represented by residential complexes within the urban fabric of the city of Baghdad. As part of following the methodology of urban dictation policies in empty areas, and to accommodate the largest number of residents as a result of the multiplicity of floors and housing, these buildings must be subject to the standards and requirements of sustainability at the level of their spatial location and their
... Show Moreobjective of this research is to identify some of the obstacles that face secondary school teachers of the Arabic language courses in using modern teaching methods in class.
The research focuses on secondary school teachers of the Arabic language courses at the central region of Nineveh Governorate for the school year (2008-2009). 30 teachers out of 792, were randomly chosen to apply the research tool upon.
To fulfill the objective of this research, the researcher first surveyed a number of teachers , he then identified four categories of obstacles; obstacles related to school administrative system and environment, the teacher, courses and pupils, and the nature of teaching method
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