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.
The main aim of this paper is to explain the effect of the aggregation accounting information on the financial, investment, and operational, managerial decision-making and the evaluation of the financial statements after aggregate. The problem of this study is represented in administrative decision-making that takes place under differentiated accounting systems operating within a governmental economic unit that seeks at the same time to achieve a unified vision and goals for the organization. This study was conducted at the College of Administration and Economics /University of Baghdad, and it represents a sample from a community of governmental economic units that apply differentiated accounting systems. The study method is repr
... Show MoreThe isolates of Staphylococcus aureus were isolated from patients with various infections in hospitals, the isolates were identified and accurately diagnosed by phenotypic examination and biochemical tests, as well Vitek-2, and then genetic detection and diagnosis of many of the pathogenic factors associated with Staphylococcus aureus using conventional polymerase chain reaction (PCR) and testing for association by antibiotic resistance and production of some toxins by Staphylococcus aureus. After performing analysis of statistical, it was set up that the correlation coefficient of the PCR technique using virulence genes, sensitivity test to antibiotics and other virulence factors were significant at p < 0.05, but was insignificant with the
... Show MoreA competitive adsorption of Cu2+, Ni2+, and Cd2+ ions from a synthetic wastewater onto nanomaterial was studied.(Fe3O4) nanoparticles obtained from US Research Nanomaterials, Inc., Houston, TX 77084, (USA), was used as nanosorbent. Experimental parameters included pH, initial metal concentrations, and temperature were studied for nanosorbent. The uptake capacity 11.5, 6.07 and 11.1 mg/g for Cu2+, Ni2+and Cd2+, respectively, onto nanosorbent . The optimum pH values was 6 and the contact time was 50 min. for Cu2+, Ni2+and Cd2+, respectively. The equilibrium isotherm for
... Show MoreThis paper details the process of designing, analysing, manufacturing, and testing an integrated solid-state hydrogen storage system. Analysis is performed to optimise flow distribution and pressure drop through the channels, and experimental investigations compare the effects of profile shape on the overall power output from the fuel cell. The storing of hydrogen is given much attention in the selection of a storage medium, and the effect of a cooling system to reduce the recharging time of the hydrogen storage vessel. The PTFE seal performed excellently, holding pressure over 60 bar, despite requiring changing each time the cell is opened. The assembly of the vessel was simple and straightforward, and there was no indication of pressure
... Show MoreThe objective of the research is to identify the nature of voluntary disclosure of insurance services and its impact on the financial performance of Iraqi insurance companies by knowing the relationship between increasing disclosure of financial services and financial performance indicators of insurance companies.In order to achieve this objective, the research was applied to a sample of the Iraqi insurance companies listed in the Iraqi Stock Exchange (Al Amin Insurance Company, Al Ahlia Insurance, Dar Al Salam Insurance, Gulf Insurance, Al Hamra Insurance) and based on their published financial statements (2014-2015) ) And by analyzing the sample lists were connected to the research objectives.The main conclusion of the study is that in
... Show MoreThe derivatives formed after the successive acetylation, esterification and nitration reactions to cholic, deoxycholic, and taurocholic acids were identified to be of the following general strucure: Colt, Where RI=NO3, OH, 0=, or CH3COO. R2=H, NO3, OH, 0-=, or CH3COO. R3=H, NO3,01-1, 0=, or CH3COO. R4=OH, NH(CH2)2S03Na, NH(CH2)2S03H, or OMe. By using U.V-visible and I.R spectrophotometry . The number of hydroxyl groups was determined, purity was checked from T.L.C, Most of these derivatives will find pharmaceutical application.
This research concerns study the crack growth in the wall of pipes made of low carbon steel under the impact load and using the effect of hygrothermal (rate of moisture 50% and 50℃ temperature). The environmental conditions were controlled using high accuracy digital control with sensors. The pipe have a crack already. The test was performed and on two type of specimens, one have length of 100cm and other have length 50cm. The results were, when the humidity was applied to the pipe, the crack would enhance to growth (i.e. the number of cycles needed to growth the crack will reduce). In addition, when the temperature was increase the number of cycles needed to growth the crack are reduced because the effect of heat on the mechanical pro
... Show MoreIn this research, the program SEEP / W was used to compute the value of seepage through the homogenous and non-homogeneous earth dam with known dimensions. The results show that the relationship between the seepage and water height in upstream of the dam to its length for saturated soil was nonlinear when the dam is homogenous. For the non-homogeneous dam, the relationship was linear and the amount of seepage increase with the height of water in upstream to its length. Also the quantity of seepage was calculated using the method of (Fredlund and Xing, 1994) and (Van Genuchten, 1980) when the soil is saturated – unsaturated, the results referred to that the higher value of seepage when the soil is saturated and the lowe
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