In this research, damping properties for composite materials were evaluated using logarithmic decrement method to study the effect of reinforcements on the damping ratio of the epoxy matrix. Three stages of composites were prepared in this research. The first stage included preparing binary blends of epoxy (EP) and different weight percentages of polysulfide rubber (PSR) (0%, 2.5%, 5%, 7.5% and 10%). It was found that the weight percentage 5% of polysulfide was the best percentage, which gives the best mechanical properties for the blend matrix. The advantage of this blend matrix is that; it mediates between the brittle properties of epoxy and the flexible properties of a blend matrix with the highest percentage of PSR. The second stage included reinforcing the best blend matrix of epoxy-polysulfide (the blend matrix with the best percentage of polysulfide resulted from the previous stage), by different volume percentages of short fibers (Carbon& Glass) separately and randomly. The volume percentages of fibers were (2.5%, 5%, 7.5%, and 10%). The third stage included reinforcing the blend composites with highest percentages of carbon and glass fiber, by different weight percentages of nano-particles (Red mud& Fly ash) separately. The weight percentages of particles were (0.5%, 1%, 1.5%, and 2%). The experimental results showed that blending polysulfide rubber with epoxy increased the damping ratio. As for reinforcement materials, they decreased the damping ratio, where glass fiber composites have significantly higher damping ratio than other composites.
Background: Depression, a state of low mood and aversion to activity, can affect people's thoughts, behavior, tendencies, feelings, and sense of well-being. It can either be short-term or long-term, depending on the severity of the person's condition. Risk factors include personal or family history of depression, major life changes, trauma, stress, certain physical illnesses, and medications.
Objective: This study investigates the prevalence of depression among medical students at the University of Baghdad, college of medicine in Iraq, and the association between some variables and depression.
Subjects and Methods: A cross-sectional study design with a convenience sampling method was conducted.
... Show Moreهدف البحث الى التعرف على العلاقة والاثر بين متغيرات البحث والمتمثلة بأخلاقيات الاعمال بمثابة متغير مستقل بأبعاده ( فريق العمل ، المسؤولية ، السرية ، القواعد والاجراءات الوظيفية ) ومحاسبة المسؤولية بمثابة متغير تابع، ومتغير وسيط هو الثقافة ، تمثل مجتمع البحث بمجموعة من الشركات الصناعية العراقية وتم اخذ عينة قصدية من محاسبي تلك الشركات بلغ عددهم (60) محاسبا حيث تم توزيع الاستبانة عليهم كأداة للبحث وتم تحليلها ب
... Show MoreThe behavior investigation of castellated beams with fiber-reinforced lightweight concrete deck slab as a modified choice for composite steel-concrete beams affected by harmonic load is presented in this study. The experimental program involved six fixed-supported castellated beams of 2140mm size. Three types of concrete were included: Normal Weight Concrete (NWC), Lightweight Aggregate Concrete (LWAC), and Lightweight Fiber-Reinforced Aggregate Concrete (LWACF). The specimens were divided into two groups: the first comprised three specimens tested under harmonic load effect of 30Hz operation frequency for 3 days, then the residual strength was determined through static load application. The second group included three specimens ide
... Show MoreThis purpose of the research is to test liquidity ratios to assess bank liquidity risks represented by liquidity ratios (current assets / current liabilities, current assets / total deposits, current assets / total assets, cash credit / total deposits, liquidity coverage ratio LCR, net stable financing ratio NSFR). This research involves evaluating these risks in banks via these ratios, and reveal the most important means used to solve these risks, including the capital adequacy ratio under the Basel II decisions and for selected period (2017-2019).The research reached the most important conclusion, which is the bank sample did not fall into bank liquidity risks throughout the years of research. Tracking specific ratio with adequ
... Show MoreThe revolution of technology in the 21st century has changed radically the
climate of opinion concerning second language education. In order to excel in
today’s world, teachers and learners need to adopt new roles and be equipped with
new skills and competencies that go beyond the basic ones of listening, speaking,
reading, and writing; skills that cannot be gained if teachers teach mere academic
subjects, and students are evaluated on how well they have learnt the minute sub
skills in those content areas.
This session will touch upon several skills which may be considered the
new basics of the 21st century. Among these skills are: autonomy, active learning,
critical thinking, cooperative learning, and digita
Praise be to God, Lord of the worlds, and peace and blessings be upon our master Muhammad and his family and companions as follows:
This research examines altruism in the Noble Qur’an objectively. The altruism is a word that permeates selection, preference, presentation, types of gifts, and all other material and moral virtues. It is the highest level of generosity and generosity, provided that the consent of God Almighty is enriched on the consent of others, and that greatness arises in it, and that creation affects On yourself in what does not deprive you of a religion, and it does not cut you off on a path, because the praiseworthy altruism is only in relation to souls, not the disgraced altruism tha
Keeping the secret itself of topics for values are positive attribute of personality traits balanced. Objective of this research study of Keeping the secret when spouses, the study of the theory based on the research and literature that dealt with the subject study is important to mention that there was no study of one Iraqi addressed the study of Keeping the secret when spouses.
The researcher found the importance of the study of it's Keeping the secret when spouses. the factors that affect family relationships in terms of the stability of the marital relationship and this is reflected positively on the lives of family and community.
... Show MoreThe bourgeoisie groups derived great advantages from the system upon which the Fatimids built up their Regime out the land-tax and other taxes against a fixed sum . The surpulus revenue was the prophet of the farmers . A striking feature of the Fatimid was freedom of enterprise .All sectors of economic life were free-crafts , industry and trade . The government interfered in the trade in victuals only so far to in order to guarantee the supply of wheat to the big towns
The Egyptian Bourgeoisie enjoyed also the great prosperity which was produced among other reasons by the inflationary system of Fatimid economy .
The maintenance of gold dinar being almost pure and of full weight was only possible because Egypt steadily received cons