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.
This experiment was performed to investigate the effect of dietary supplementation with linseed on egg quality of laying quail. A total of 320 9-week-old Japanese quail (Coturnix coturnix japonica) 9-wk old were allocated to 4 treatment groups with 4 replicates containing 20 quail each. Birds were fed a commercial diet containing 0% (C), 2% (T1), 4% (T2), or 6% (T3) linseed. Birds received water and diet ad libitum during the total period of the experiment. Egg quality characteristics were monitored over 3 consecutive 21-d periods. Egg quality criteria involved in this experiment were egg weight, yolk diameter, yolk height, yolk weight, albumen height, albumen weight, shell weight, shell thickness, Haugh unit, albumen percentage, yolk perce
... Show MoreLogic is one of the sciences that have receded and regressed in the field of Islamic sciences. This regression is the result of several factors, the most important of which are:
1- The Aristotelian logic, concerned with the seemingly essential shape and the underlying truth in the text, which has been translated into Arabic, is no longer able to keep pace with scientific revelations and epistemological spaces of our time.
2- The existence of logic in the curricula of Islamic studies was not subject to a study linking logic and Islamic sciences. Therefore, we find that the student studies logic as if it were a strange subject that has nothing to do with the subjects of Islamic studies and even Islamic philosophy.
3- Logic is
Construction joints are stopping places in the process of placing concrete, and they are required because in many structures it is impractical to place concrete in one continuous operation. The amount of concrete that can be placed at one time is governed by the batching and mixing capacity and by the strength of the formwork. A good construction joint should provide adequate flexural and shear continuity through the interface.
In this study, the effect of location of construction joints on the performance of reinforced concrete structural elements is experimentally investigated.
Nineteen beam specimens with dimensions of 200×200×950 mm were tested. The variables investigated are the location of the construction joints
... Show MoreProposals to raise awareness of the rights of minorities and secure their freedoms have begun to receive attention Internationally. It is escalated, especially after the increasing impact of wars and conflicts on these situations Minorities, and UNESCO stresses the need to take over information and communication policies Greater attention to protect minority rights.
Hence the importance of our research, the problem of which lies in the main question: (What is the role Radio Republic of Iraq has played in promoting awareness of minority rights at the level : Public and Social?) . As one of the Iraqi media networks , laws oblige them to pay attention to the rights of minorities and to spread a culture of pluralism , diversity
... Show MoreThe present research deals with the study of the symmetries of the design of interior spaces in fast food restaurants in terms of formality as it is an important element and plays a direct role in the spatial configuration, which is designed in both of its performance, aesthetic and expressive aspects. Since the choice of shapes is a complex subject that has many aspects imposed by functional and aesthetic correlations, the problem of the research is represented by the following question: (To what extent can the symmetries of the interior design be used in the spaces of fast food restaurants?)
The research acquires its importance by contributing to the addition of knowledge to researchers, scholars, companies and the specialized publ
Idioms are a very important part of the English language: you are told that if you want to go far (succeed) you should pull your socks up (make a serious effort to improve your behaviour, the quality of your work, etc.) and use your grey matter (brain).1 Learning and translating idioms have always been very difficult for foreign language learners. The present paper explores some of the reasons why English idiomatic expressions are difficult to learn and translate. It is not the aim of this paper to attempt a comprehensive survey of the vast amount of material that has appeared on idioms in Adams and Kuder (1984), Alexander (1984), Dixon (1983), Kirkpatrick (2001), Langlotz (2006), McCarthy and O'Dell (2002), and Wray (2002), among others
... Show MoreA numerical investigation is adopted for two dimensional thermal analysis of rocket thrust chamber wall (RL10), employing finite difference model with iterative scheme (implemented under relaxation factor of 0.9 for convergence) to compute temperature distribution within thrust chamber wall (which is composed of Nickel and Copper layers). The analysis is conducted for different boundary conditions: only convection boundary conditions then combined radiation, convection boundary conditions also for different aspect ratio (AR) of cooling channel. The results show that Utilizing cooling channels of high aspect ratio leads to decrease in temperature variation across thrust chamber wall, while no effects on heat transferred to the
... Show MoreThe artistic concepts differ in their expressive and semantic relations, among these concepts are the artistic values, as there are points of view, social concepts and historical values interacted from one generation to another over the time. These values represent symbols and indications reflect reality, which has passed through the time to reach us with environmental forms saved by the history at the Natural History Museum, has an impact on the receives mind with its formal and sensory dimensions and connecting with that history as an environment that lacks to the current reality which has immortal means particularly in the cognitive thinking , and the reflection of that in the Iraqi culture and with the associated concepts of interior
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