A numerical investigation has been performed to study the effect of eccentricity on unsteady state, laminar aiding mixed convection in a horizontal concentric and eccentric cylindrical annulus. The outer cylinder was kept at a constant temperature
while the inner cylinder was heated with constant heat flux. The study involved numerical solution of transient momentum (Navier-Stokes) and energy equation using finite difference method (FDM), where the body fitted coordinate system (BFC) was
used to generate the grid mesh for computational plane. The governing equations were transformed to the vorticity-stream function formula as for momentum equations and to the temperature and stream function for energy equation.
A computer program (Fortran 90) was built to calculate the bulk Nusselt number (Nub) after reaching steady state condition for fluid Prandtl number fixed at 0.7 (air) with radius ratio ( =2.6), Rayleigh number (Ra=200), Reynolds number (Re=50) for both concentric and eccentric cylindrical annulus with different eccentricity ratios (ε=0, 0.25, 0.50, 0.75) and angular positions (φo=0o
, 45o , 90o , 135o , 180o ).
The results show a reasonable representation to the relation between Nusselt number and (ε, φo). Generally, Nub decreased with the increase in (ε and φo). Also, results show that the best thermal performance for the inner cylinder was at the angular
position (φo=0o ) for eccentricity ratio (ε=0.25), while the maximum reduction in the rate of heat transfer for the inner cylinder was at the angular position (φo=180o) for eccentricity ratio (ε=0.75).
Comparison of the result with the previous work shows a good agreement.
Isthmus life and prepare for it
Background: A major difference between the treatment of the skin lesions and the odontogenic and non-odontogenic sinuses. We aimed to analyze a substantial number of consecutive causes in order to clinical suspicion in the differential diagnoses may be correctly weighted. Materials and methods: The material of this research consisted of 40 patients. A complete history is collected from the patients with the duration and the site of the sinus present, the patient was examined for factors of the fistulas and sinuses and its associations, and patient having any concomitant lesions, a medical consultation done for opinion and management. Clinical examination with facial fistulas and sinuses was mandatory to avoid any mistakes that may occur. A
... Show MoreIncreasingly important public opinion polls steadily .... especially in electoral campaigns, sheds searchlight on the side of the US elections, in different time periods, and cited the words of experts and people involved in it, and reviews Find great development that took place in the polls and what could happen to this work It is important in the future. Display search for certain types of polls, dividing them on as stated by the experts in the United States... This division shows that the surveys of the most political processes and accuracy of information, and that their Money being made and companies specialized in the administration of this type of measuring public opinion ..... what is returned decision-making, for example, in conj
... Show MoreThe presence of research Repositories in the intellectual production of universities and their availability through their websites or through their scientific institutions is one of the criteria for evaluating these universities in the international classifications of the best universities, in addition to preserving the intellectual output of these universities for a long time and safely and preserving the property rights of researchers. And made them available through their websites. The purpose of this research is to identify the concept of digital content and research repositories and its origin, and to indicate the importance of its existence through the websites of universities and their types, and to identify the research repositories
... Show MoreMan has a great role in the development of society in all fields, and therefore the human thought played a great role in its continuous pursuit and insight into the social classes that differ in their privileges, which makes the members of society not reconcile because of that disparity that is not based on human principles, so one class exploits another, and this is what stopped me Rather, it prompted me to choose the topic (class and its impact on society) in order to show the impact of classes on each other negatively and positively, so I work to avoid the first with the recommendations I put forward and offer guidance, and strengthen the second, and after this topic of necessity in a place because of the imbalance and promise of appr
... Show MoreIn this paper, we introduce a new concept named St-polyform modules, and show that the class of St-polyform modules is contained properly in the well-known classes; polyform, strongly essentially quasi-Dedekind and ?-nonsingular modules. Various properties of such modules are obtained. Another characterization of St-polyform module is given. An existence of St-polyform submodules in certain class of modules is considered. The relationships of St-polyform with some related concepts are investigated. Furthermore, we introduce other new classes which are; St-semisimple and ?-non St-singular modules, and we verify that the class of St-polyform modules lies between them.
In this work we discuss the concept of pure-maximal denoted by (Pr-maximal) submodules as a generalization to the type of R- maximal submodule, where a proper submodule of an R-module is called Pr- maximal if ,for any submodule of W is a pure submodule of W, We offer some properties of a Pr-maximal submodules, and we give Definition of the concept, near-maximal, a proper submodule
of an R-module is named near (N-maximal) whensoever is pure submodule of such that then K=.Al so we offer the concept Pr-module, An R-module W is named Pr-module, if every proper submodule of is Pr-maximal. A ring is named Pr-ring if whole proper ideal of is a Pr-maximal ideal, we offer the concept pure local (Pr-loc
... Show MoreIn this thesis, we introduce eight types of topologies on a finite digraphs and state the implication between these topologies. Also we studied some pawlak's concepts and generalization rough set theory, we introduce a new types for approximation rough digraphs depending on supra open digraphs. In addition, we present two various standpoints to define generalized membership relations, and state the implication between it, to classify the digraphs and help for measure exactness and roughness of digraphs. On the other hand, we define several kinds of fuzzy digraphs. We also introduce a topological space, which is induced by reflexive graph and tolerance graphs, such that the graph may be infinite. Furthermore, we offered some properties of th
... Show MoreJurisprudence purposes Anwash and his importance