The printed circuit heat exchanger is a plate type heat exchanger with a high performance and compact size. Heat exchangers such as this need a unique form of bonding and other techniques to be used in their construction. In this study, the process of joining plates, diffusion bonding, was performed and studied. A special furnace was manufactured for bonding purposes. The bonding process of copper metal was carried out under specific conditions of a high temperature up to 700 oC, high pressure of 3.45 MPa, and in an inert environment (Argon gas) to make tensile samples. The tensile samples are cylindrical shapes containing groves representing the flow channels in the printed circuit heat exchanger and checking their tensile strength in addition to the standard shape of the tensile specimen to check the yield and ultimate strength of the copper. A higher tensile strength was obtained for diffusion bonded specimens than the yield strength of copper, up to 1.35 times the copper yield strength. The tensile strength decreases with the increase in the number of groves and the decrease in the distance between one grove and another. This is because the stress is concentrated in the sharp corners. A prototype heat exchanger of two plates and a header to be tested for its compressive strength was also manufactured. The results showed that the bond bears an air pressure of up to 8 bar without fail. It was also found to withstand a hydraulic pressure of up to 60 bar until it reached failure.
In recent years, the attention of researchers, governments and international non-governmental organizations has focused on the aggressive practices adopted by companies with the aim of evading the tax burden or from paying the tax obligations imposed on them by law, as the results of these practices are negatively affected by tax revenues. And that companies are part of the society in which they work, and they have rights and obligations, including paying taxes. The research community is the Iraqi private shareholding companies, and the research sample was 4 companies within the private sector and in the field and finance - banking, insurance, industrial and service, which are Ashur Bank, Al-Ahlia Insurance Company, Baghdad Soft
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The study aims to find out the degree of practicing professional leadership of the faculty’s deans, deputies, and heads of the scientific divisions at Al-Qaseem University. The study has adopted the descriptive analytical method. To achieve the objective of the study, the researcher developed a questionnaire consisting of (45) items distributed to six fields that were applied to a sample of (116) faculty deans, deputies, and the head of division at Al-Qaseem University. The results showed there is a high practicing degree of the study sample individuals of the professional leadership on the questionnaire’s fields as a whole, strategic thinking field came at the first rank, while the innovation, creat
... Show MoreThe banking sector is a cornerstone of the national economy because of its large role of economic development of a country, which requires the advancement of this vital sector and interest in all the accompanying changes to him in order to survive and grow and continue Accordingly dealt Find reversal (organizational culture, on the quality of banking service ) sought search to achieve a number of cognitive and practical goals by selecting (10), especially among the working banks in Iraq Iraqi banks and the period is the surveyed period (2005-2014) embodied the research problem in the dialectical relationship between the (organizational culture) and its impacts on banking service quality.
Through a set of
... Show MoreThe study aims to know the nature of the expected relationship between market share management strategies and the variation in the performance of the shares of a number of Iraqi industrial companies listed in the Iraqi Stock Exchange. For the period (2005-2018) in the light of both the monthly closing prices and sales volume during the research period, the (Panel Data) method was relied on through a stylistic test (fixed effects model and random effects model), and the results determined the need to adopt the fixed effects model method for sample data and test Assumptions, the results showed the positive impact of market share according to its strategies on the performance of stocks according to its studied indicators (Treynor index
... Show MoreAbstractIn the field of construction materials the glass reinforced mortar and Styrene Butadiene mortar are modern composite materials. This study experimentally investigated the effect of addition of randomly dispersed glass fibers and layered glass fibers on density and compressive strength of mortar with and without the presence of Styrene Butadiene Rubber (SBR). Mixtures of 1:2 cement/sand ratio and 0.5 water/cement ratio were prepared for making mortar. The glass fibers were added by two manners, layers and random with weight percentages of (0.54, 0.76, 1.1 and 1.42). The specimens were divided into two series: glass-fiber reinforced mortar without SBR and glass-fiber reinforced mortar with 7% SBR of mixture water. All s
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Gabriel Garcia Marquez, the Nobel laureate of literature in 1982, is one of the most famous Latin American writers who have been distinguished by the magic of realism. We can say the months in the world and he is almost the most controversial for many reasons and for these reasons he did not accept that his novels turn into movies Marquez agreed to turn one of his most important and most beautiful novels, "Love in the Time of Cholera," which he wrote in 1985 and agreed to convert to a film in 2006 after the novel was bought by the author for $ 3 million. Mike Noel to bring out
Background: Recurrent Aphthous Stomatitis (RAS) is the most common painful oral mucosal disease, affecting approximately 20% of the population. RAS presents with a wide spectrum of severity ranging from a minor nuisance to complete debility. Many of factors thought to have been involved in its etiology; that might have at the same time a direct or indirect impact upon oxidant/antioxidant system and trigger free radicals production. The aim of this study was to determine the possible association of oxidant/total antioxidant status and recurrent aphthous stomatitis (RAS). Subjects, materials and methods: The study consisted of thirty patients with recurrent aphthous stomatitis and thirty healthy controls from which saliva and blood samples we
... Show MoreAfter completing the research, with the help and success of God Almighty , I will summarize what has been mentioned in a concise and understandable form, without boring prolongation or abbreviation .
The subject, in general, was clarified, clarified and corrected, as I mentioned, for an incorrect concept, about paying zakat on trade goods.
It has known trade offers parts and combination of language and idiomatic .
The rule of zakat on trade goods, and evidence from the Qur'an, Sunnah and consensus .
As well as the conditions of its zakat according to the jurists and their differences in it .
It
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This study deals with the fluctuations of oil revenues and its effect on the public debt. This can be studied through the indicators of debt sustainability, the financial, and economic indicators which express the risk of debt. The study focuses on clarification of the public debt path and its management both domestic and foreign. The sustainability of debt takes an important role according the macroeconomic variables. This study stresses the relationship between the rental economy in Iraq and the risk of the public debt, it is very important to work high oil prices, and on investigating during high work to establish a fund to support the budget deficit. This will reduce future risks arising from the use of publi
... Show MoreThe current research aims to identify the impact of the (Landa) model on acquiring grammatical concepts among students of the College of Administration and Economics, University of Baghdad, and to achieve the research goal, the researcher has set the following hypotheses: There are no statistically significant differences at the level of significance (0.05) between the average degrees Students of the experimental group who studied the Arabic language according to the (Landa) model and the marks of the students of the control group who studied the same subject in the usual way in the post test, there are no statistically significant differences at the level of significance (0.05) in the average differences between the test scores before and
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