The investigation of natural convection in an annular space between two concentric cylinders partially filled with metal foam is introduced numerically. The metal foam is inserted with a new suggested design that includes the distribution of metal foam in the annular space, not only in the redial direction, but also with the angular direction. Temperatures of inner and outer cylinders are maintained at constant value in which inner cylinder temperature is higher than the outer one. Naiver Stokes equation with Boussinesq approximation is used for fluid regime while Brinkman-Forchheimer Darcy model used for metal foam. In addition, the local thermal equilibrium condition in the energy equation of the porous media is presumed to be applicable for the present investigation. CFD ANSYS FLUENT software package (version 18.2) is used as a solver to this problem. Various parameters are examined; Rayleigh number, Darcy number, and thermal conductivity ratio to study the effect of them on fluid flow and heat transfer inside the annuli space in the suggested design of metal foam layer. current model is compared with the available published results and good agreement is noticed. Results showed that as Rayleigh number increases the dominated of convection mode increases and Nusselt increases. Also, Nusselt is larger at the higher Darcy and thermal conductivity ratio. It was found that at Rayleigh of 106 and thermal conductivity ratio of 104 Nusselt reach its higher value which is 6.69 for Darcy of 0.1 and 6.77 for Darcy of 0.001. A comparison between this design and the traditional design was established for Darcy 0.001 and thermal conductivity ratio 102, and its showed a good enhancement in Nusselt number and the greatest enhancement percentage was 44% at Rayleigh equal 5*104 while the lowest percentage is 6% for Rayleigh equal106.
The two objectives of the current research are :-
- Uncover the views and opinions of the students of Artistic Education Department about the relation between educational novelty and its relation with visual .
- Identifying the capabilities of the students of artistic education department .
The society of the research is the fourth class students of artistic education department - College of Fine Arts ( 83 students from both sexes ) . It was chosen ( 60 ) students sample of from both sexes by the researcher in order to conduct test upon them .The researcher has adopted descr
... Show MoreThe current study aimed to identify key consumer rights and the nature of the work of organizations and traders in the Algerian market through the opinions of the study sample. To prove the hypotheses the researcher depended on the data obtained by the questionnaire prepared for this purpose. She distributed 384 questionnaires out of which only 300 were returned.
The data were analyzed using several statistical techniques such as the Statistical Package for Social Studies system, in addition to percentages, frequencies, and standard deviation.
And a number of conclusions and recommendations were presented. The most important results are:
- There is a strong correlation between safety and compensation rights.
- There is a st
Sex chromatin (SC) is defined as inactive X chromosome in the female somatic cells, it condensed as heterochromatic at interphase of the nucleus and appears like nuclear satellite projection, and only female cells contain SC in mammals. Different ages of cocks: immature (8,16 weeks old), growing (24 weeks old) and production age (32,48 weeks old) , were studied to detect the sex chromatin (SC) with it's various shapes :Sessile nodule(SS), Drum stick(DS), Tear drop(TD) and Club shape(CS) in the blood lymphocytes of blood smears prepared from WBCs of 45 New Hampshire(NH) strain cocks. Also SC measurements were detected which include: vertical (V) and horizontal (H) axes, SC area (SCA), nuclear area (NA), and the
... Show MoreBackground: Helicobacters are motile curved, oxidase and catalase positive,
gram negative rods similar in morphology to vibrios. The cells have polar flagella
and are often attached at their ends given pairs "S" shapes or seagull
appearance.
Object i ves: The present study was undertaken to estimate the serodiffusion of
H. pylori and hepatitis A virus (HAV) in 300 patients attending two centers in
Baghdad.
Metthods:: HAV was determined by the detection of HAV-IgM in the serum samples. Detection of H. pylori was by ELISA and endoscopic examination.
Resul t s: The serodiffusion of H. pylori was 40% (n=120). Out of the 120
patients infected with H. pylori, 50(41 .6%) patients were diagnosed clinically to
have g
High-power density supercapacitors and high-energy–density batteries have gotten a lot of interest since they are critical for the power supply of future electric cars, portable electronic gadgets, unmanned aircraft, and so on. The electrode materials used in supercapacitors and batteries have a significant impact on the practical energy and power density. Metal–organic frameworks (MOFs) have the outstanding electrochemical ability because of their ultrahigh porous structure, ease of functionalization, and great specific surface area. These features make it an intriguing electrode material with good electrochemical efficiency for high-storage batteries. Thus, this review summarizes current developments in MOFs-based materials as an elec
... Show MoreEfficacy of Varnishes with: Bioactive Glass, Recaldent Technology and Silver Diamine Fluoride in Comparison with Sodium Fluoride on Tooth Surface Micro-hardness (an In Vitro Study)
In this study, gamma-ray spectrometry with an HPGe detector was used to measure the specific activity concentrations of 226Ra, 232Th, and 40K in soil samples collected from IT1 oil reservoirs in Kirkuk city, northeast Iraq. The “spectral line Gp” gamma analysis software package was used to analyze the spectral data. 226Ra specific activity varies from 9 0.34 Bq.kg-1 to 17 0.47 Bq.kg-1. 232Th specific activity varies from 6.2 0.08 Bq.kg-1 to 18 0.2 Bq.kg-1. 40K specific activity varies from 25 0.19 Bq.kg-1 to 118 0.41 Bq.kg-1. The radiological hazard due to the radiation emitted from natural r
... Show MoreLocal food samples investigated for the presence of pathogenic bacteria. Hash meat sample was used to isolate Escherichia coli and chicken meat (poultry) was used to isolate Salmonella typhi. Biochemical tests and API20E system used in order to identify these isolates. Two natural vinegar samples (dates & apple cider) were used in order to study its antibacterial activity against the two tested bacteria. Disc diffusion method was used, the results showed that two vinegar samples have antibacterial activity against the two tested bacteria. Date vinegar showed inhibition zone 19mm against E. coli & 9mm against S. typhi, while Apple cider vinegar showed diameter of inhibi
... Show More
