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.
A significant influence of temperature width found on the vanadium oxide properties, it plays a major role in highlighting the thermal limits of the three phases (metallic, semiconductor, and dielectric). Two values of the temperature width , and , had taken and studied their effect on both the dielectric constant and its two parts; refractive index, and extinction coefficient, and. It found that: as the temperature width is greater, the more the properties of the three phases for . In addition to increasing the thermal range for phases which can be reached to when , while it's at . Our results have achieved great compatibility with the published results globally. In addition to the effect of both ultraviolet, visible, and infrared
... Show MoreObjectives: The aim of the study was, to assess the nurse's role regarding cardiovascular drug
administration in Erbil city.
Methodology: A descriptive survey was conducted in Hawler teaching and Rizgari teaching Hospitals. The
number of samples is 50 nurses; the period of the study was started from 15th of November 2008 up to
the end of March 2009. A questionnaire was developed by investigators based on extensive review of
available studies and literatures. Data were collected through application of observational check list
consist of two part, part one was demographic sheet and part two about nurse’s responsibility regarding
medication administration which include (before, during, after drug administration). Data
Many behavioral researchers pointed out the importance of relaxation techniques in the treatment of different psychological disorders where find the importance of these techniques in reducing anxiety and stress and the resulted of behaviors and habits, with the development of these techniques are being used to gain public health, whether mental health or physical or mentality, and one of these techniques is music therapy that reduces tension and anxiety and operates a state of relaxation, which is used in the treatment of patients of dental clinic.
Re
... Show MoreThis paper experimentally investigated the dynamic buckling behavior of AISI 303 stainless steel aluminized and as received intermediate columns. Twenty seven specimens without aluminizing (type 1) and 75 specimens with hot-dip aluminizing at different aluminizing conditions of dipping temperature and dipping time (type 2), were tested under dynamic compression loading (compression and torsion), dynamic bending loading (bending and torsion), and under dynamic combined loading (compression, bending, and torsion) by using a rotating buckling test machine. The experimental results werecompared with tangent modulus theory, reduced modulus theory, and Perry Robertson interaction formula. Reduced modulus was formulated to circular cross-
... Show MoreThis research study focuses on fundamental questions. It deals with the content of the critical reviews through which the most important sources that undermine the renaissance of the Islamic human society can be concluded. It is the vague fetishization of the sacred between religion, politics, and ideas, which members of society live in and which raised the dust of closed-minded fanaticism that led to the return of deviant extremism. It is oppression, violence, and domination, all of which are professional tools in the manufacture of the ideology of extremism in all its forms. Here, the idea matured in giving a human, intellectual and philosophical overview that mixed the required drawing in the formulation of scientific cont
... Show MoreThe chemicals materials were used to study the effect of citric acid, detergents, sodium carbonate, sodium bicarbonate on the vitality of the third stage of mosquito Culex pipiens molestus. The highest larvicidal efficacy was established from citric acid solution followed by detergents solution, sodium carbonate, sodium bicarbonate with (LC50) values 2096, 2715, 13930, 13960 ppm respectively. The concentration of 1000 ppm of citric acid showed a fatal effect on the third stage larvae of mosquitoes which gave a mortality percent of 100% on the second day of the treatment. It was followed by the concentrations of 750 ppm and 500 ppm respectively which caused the death of all larvae on the fifth and sixth days respe
... Show MoreThe aim of this study is to propose mathematical expressions for estimation of the flexural strength of plain concrete members from ultrasonic pulse velocity (UPV) measurements. More than two hundred pieces of precast concrete kerb units were subjected to a scheduled test program. The tests were divided into two categories; non-destructive ultrasonic and bending or rupture tests. For each precast unit, direct and indirect (surface) ultrasonic pulses were subjected to the concrete media to measure their travel velocities. The results of the tests were monitored in two graphs so that two mathematical relationships can be drawn. Direct pulse velocity versus the flexural strength was given in the first relationship while the second equation des
... Show MoreThe research attempts to identify the pattern of punctuation in contemporary Iraqi poetry through delving into the poetry of an Iraqi poet belonging to the seventieth generation, Namik Abdul Deeb, who belongs to the poets of Arab modernity in general, the research has reached many results, including that the signs of deletion were vocabulary marks any They are located in the center of the poetic singular, or inline markers, which are those that fall within the poetic line of the prose poem separating its vocabulary, or cross-sectional marks located within the poetic passages that are part of the poetic text, and finally text marks which are located within the poetic text and fragmented into Parts. The research also found that the work of
... Show MoreToday technology using nanoparticle when treatment pathogentic microorganism and we focused on this here. It was found that the species of streptococcus used in present study were sensitive to erythromycin. In present study focusing biofilm formation by Streptococcus spp was evaluated. Species S. mutans was found that highest amount of biofilm compare with the other species. The aim of report effect (SNPs) on ability of biofilm form different species of streptococcus. The anti-biofilm effect of SNPs was in concentration dependent manner. The highest effect of SNP against biofilm formation was found the concentration 160 μg/ml, while the lowest effect was found the lowest used concentration (80 μg/ml) of SNPs. In vivo study revealed that s
... Show MoreThe Chemistry of heterocyclic sulphur and nitrogen containing compounds have a great role in the field of scientific studies, The 2-amino 5-mercapto-1,3,4-thiadiazole ring for instance, has gained more importance in recent years because they are considered as potent biologically active nucleus. In this study disulfide derivative can be obtained by oxidation with hydrogen peroxide of thiol group of the heterocyclic 2-amino 5-mercapto-1,3,4-thiadiazole ring to obtain compound (3) with expected antibacterial activity. In order to use it as a diazo component to prepare some new bis azo compounds as possible antibacterial agents, the reaction of two primary amino groups on both sides of disulfide dimer with sodium nitr
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