In this study, thermal characteristics of a two-phase closed heat pipe were investigated experimentally and theoretically. A two-phase closed heat pipe (copper container, Fluorocarbon FC-72 (C6F14) working fluid) was fabricated to examine its performance under the effect of input heat flux range of 250–1253 W/m2 , 70% fill charge ratio and various tilt angles. The temperature distribution along the heat pipe, input heat to evaporator section, and output heat from condenser were monitored. A comprehensive mathematical model was developed to investigate the steadystate heat transfer performance of a two-phase closed heat pipe. A steady state analytical model, is presented to determine important parameters on the design of two-phase closed heat pipe, including temperature levels and heat transfer coefficients for condenser and evaporator. The experimental and simulation results of this work are found in good agreement. The experimental boiling heat transfer coefficients were compared with existing previously reported correlations.
A study of the singlet and triplet states of two electron systems in the first excited state was performed using a simple quantum mechanical model, which assigns the 1s,and 2s orbital with two different variational parameters. Our results agree with a high level calculation used by Snow and Bills.
Some research reports that cognitive grammar (CG) theory has good contributions to teaching English as a foreign language. In this research, the researchers seek to apply this theory and its principles when teaching the simple present tense to Iraqi students who face difficulties in differentiating between the multiple usages of this tense. To achieve this objective, the researchers have conducted an experimental study on a group of 60 Iraqi students in the University of Baghdad, College of Education for Women. Langacker’s (2003) theory has been adopted in the analysis of the cognitive relations to understand the common and different connections of these usages of the simple present. The study has concluded that the cognitive grammar t
... Show MoreNi2O3 nanomaterial, a phase of nickel oxide, is synthesized by a simple chemical process. The pure raw materials used in the present process were nickel chloride hexahydrate NiCl2.6H2O and potassium hydroxide KOH by utilizing temperature at 250 oC for 2 hour. The structural, morphological and optical properties of the synthesized specimens of Ni2O3 were investigated employing diverse techniques such as XRD, AFM, SEM and UV-Vis, respectively. The XRD technique confirms the presence of Ni2O3 nanomaterial with crystal size of 57.083 nm which indexing to the (2θ) of 31.82; this results revealed the Ni2O3 was a phase of nickel oxide with Nano structure. The synthesized Ni2O3 will be useful in manufacturng electrodes materials f
... Show MoreThis study Achieved to search form the infections by Cholera and Diarrhea in two different areas from the side of Cultural, Social, Economical and Environmental field in Baghdad governorate, during a period from 3/10 – 3/12/2007.these were in Obiady city and Palestine street. This study included groups of patients who went to the Kindy Hospital lab. The researcher use a sample of (300) persons of different ages with range (150) persons in each city from the study city, in this study show a great different in the percentage of infection by parasites, helminthes, viruses, bacteria and vibrio cholera in the two city according to age groups, reach upper percentage by infection in age (1-10) years in Obiady city with percent (57.5 %) wh
... Show MoreThe importance of knowledge is represented in the use of various sources of information, the corresponding to the same level of importance is the use of modern means and technologies in the delivery and investment of these sources to the beneficiaries, among these means and technologies are the multimedia that deal with most of the human senses, but the most important of which is sight and hearing, if these are invested the means in the field of education will give many positive results, such as the speed of receiving information, its clarity, and its freedom from impurities and influences, as well as its stability in memory as it is based on nderstanding, not memorization. On this basis, the experience of supporting the education process
... Show MorePerhaps the issue of media and the press, especially one of the most common topics that people deliberate and deal with permanently and continuously. An issue of such significance has pushed researchers to put the following question, “Is it possible to live without media?”, “Can people ignore the newspaper, radio, TV, or the other communication means?”
The answer is very simple. It is difficult for civilized society to overtake information, or dispense with circulation, at the individual or collective level. Yet, the question of how to make the media and how it determines its content still requires extensive media experience; and knowledge of the social structure and its relations; and ac
... Show MoreLanguage ecology is the interactions between the environment and language. Such a discipline, ‘language ecology’ or ‘ecolinguistics has been founded by Einar Haugen’. Accordingly, the study aims at qualitatively reviewing the theoretical and conceptual issues surrounding the subject of language ecology by tracing the roots of language ecology. It further highlights the fundamental inconsistencies between how the concept of ecology is perceived in sociology and biology, and is applied to language, particularly, transposing the main central concepts of bio-ecology, such as relationship/interaction, environment, and organism to human language and theory of ecological-linguistic. The theory wavers among placing the focus
... Show MoreThe concept of employees voice has received a great deal of attention by researchers in the field of organizational behavior and human resources management especially in the last three decades of the twentieth century , this importance has deep ranges limits in terms of its discussion history, so it became a behavioral variable received a great attention and care in managerial and organizational studied and basic pillar in the success and excellence of organizations in maintaining its human resources, the research explain the concept and benefits of paying attention to the voice of employees in business organizations , and the theories interpreted to employees voicing and clearing the motivations behind employees voicing, and dis
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