A 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 coolant is indicated. The radiation has a considerable effect on the computed wall temperature values.
Pseudomonas aeruginosa is an opportunistic pathogen responsible for serious infections. At least three different exopolysaccharides, alginate, polysaccharide synthesis locus (Psl), and pellicle exopolysaccharide (Pel) make up the biofilm matrix in P. aeruginosa . The effect of temperature on the biofilm formation and gene expression was examined by microtiter plate and real-time quantitative polymerase chain reaction (qRT-PCR). To be able to determine the effect of temperature on biofilm formation and gene expression of P. aeruginosa, 303 clinical and environmental samples were collected. Pseudomonas aeruginosa was isolated from 61 (20.1%) and 48 (15.8%) of the clinical and e
... Show MoreShallow foundations are usually used for structures with light to moderate loads where the soil underneath can carry them. In some cases, soil strength and/or other properties are not adequate and require improvement using one of the ground improvement techniques. Stone column is one of the common improvement techniques in which a column of stone is installed vertically in clayey soils. Stone columns are usually used to increase soil strength and to accelerate soil consolidation by acting as vertical drains. Many researches have been done to estimate the behavior of the improved soil. However, none of them considered the effect of stone column geometry on the behavior of the circular footing. In this research, finite ele
... Show MoreStylistics is the analysis of the language of literary texts integrated within various approaches to create a framework of different devices that describe and distinct a particular work. Therefore, feminist stylistics relied on theories of feminist criticism tries to present a counter- image of a woman both in language use and society, to draw attention , raise awareness and change ways that gender represents. Feminist stylistic analysis is related not only to describe sexism in a text, but also to analyze the way that point of view, agency, metaphor, and transitivity choices are unanticipatedly and carefully connected to issues of gender(Mills,1995:1) &nb
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Liquefied petroleum gas (LPG), Natural gas (NG) and hydrogen were used to operate spark ignition internal combustion engine Ricardo E6, to compare NOx emissions emitted from the engine, with that emitted from engine fueled with gasoline as a fuel.
The study was done when engine operated at HUCR for gasoline, compared with its operation at HUCR for each fuel. Compression ratio, equivalence ratio and spark timing were studied at constant speed 25rps.
The results appeared that NOx concentrations will be at maximum value in the lean side near the stoichiometric ratio, and reduced with moving away from this ratio for mixture at both s
... Show MoreConsistent with developments emerging environmental and canaccept by Iraq of the opportunities and challenges ahead in many fields,including economic areas, it requires the face of those developments andadaptation by adopting a lot of related concepts, including the concept ofcorporate governance and commitment to its principles, standards andmechanisms, especially those related to the formation of audit committeesand identify the tasks and duties entrusted to its members and terms oftheir independence as well as the rehabilitation of both scientific andpractical manner that is consistent with the interests of shareholders andother stakeholders in the companies, including banks, research sample, theresearch aims to shed light on the conc
... Show MoreIn 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
... Show MoreThe major climate changes that have affected the planet in addition to wave the big drought plaguing the study area, including the lack of water for imports Badra River fatigue because of the Iran constructing dams on this river and make use of the waters for the benefitof its territory. The subject of finding sources of water has become available with the possibility of exploiting them in an exemplary manner is one of the key things in order to be exploited somewhere.
The study area was chosen within the eastern border of the province of Wasit within the district of Badra border, an area of (1557.5 km2) almost "to study the characteristics of hydrological and identify possibilities for water harvesting them. In this study was conduct
The aim of the research is to determine the extent to which young people watch television sports programs and the impact of viewing on the level of sports culture among young people and the impact of demographic variables on youth over the viewing of sports programs, The study was conducted on a sample of (200) male and female students from the faculties of the University of Baghdad, where a questionnaire form composed of several axes and questions was prepared to measure the effectiveness of sports programs in youth culture, The statistical program used spss to empty data and extract results by frequency, percentages, correlations, The research reached several results, the most important of which is that there is a strong influence of s
... Show MoreThe book The Laws of Duwan of Mamati's Son (T, 606 E) His approach to his narratives is a topic of historical and civilized importance. The Fatimid Age of the People of Jehovah has expanded its influence and authority, including ministers, writers, doughnuts and foreshores. One of the Christian families that shined in the late Fatmi era was "Mamati", who lived in "Assiut" from Upper Egypt, then moved to Cairo, and enrolled in the service of the Fatimids, where their sons held important positions in State offices.Ibn Mamati became in charge of the Army Office and then added to it the Finance Office, which became the most important downs in Egypt. Through his work in the Duwan Law Books, this book was a living record of the Dawawans in the Ay
... Show MoreThe concern of this article is the calculation of an upper bound of second Hankel determinant for the subclasses of functions defined by Al-Oboudi differential operator in the unit disc. To study special cases of the results of this article, we give particular values to the parameters A, B and λ